Fully automatic electrochemiluminescence detector based on photodiode

Abstract

The utility model discloses a full -automatic electrochemical luminescence detector based on photodiode relates to electrochemical luminescence detection instrument, including the casing, be equipped with optical signal acquisition module, small package circuit board, ECL chip, man -machine interaction module and chip in and out device in the casing, be equipped with photoelectric current detection unit, electrochemical reaction excitation unit, microcontroller and power module in the small package circuit board, the power module is equipped with USB power supply interface and battery power supply interface. The photodiode used in the utility model can make the quick response to the change of light intensity, far faster than the speed of camera frame capture, and reduces the demand and complexity of subsequent data processing, makes the system more easily realize automation. Compared with camera, photodiode hardware cost is lower, and need not use complex image processing software, is fit for family use. The detector of the application has compact structure, and the appearance is small and exquisite, and is convenient for hand -held use and carries.

Description

Technical Field

[0001] This utility model relates to an electrochemiluminescence detection instrument, and more specifically, to a fully automated electrochemiluminescence detection instrument based on a photodiode. Background Technology

[0002] Electroluminescence (ECL) is a technique based on the generation and detection of light signals through electrochemical reactions. It combines the advantages of electrochemistry and chemiluminescence, exhibiting high sensitivity, a wide linear range, good stability, and selectivity. ECL technology typically requires specialized detectors, which generally include modules for electrochemical reaction excitation, light signal detection, and data processing.

[0003] Currently, common ECL signal detection methods analyze images captured by CCD or CMOS imaging. Image processing techniques are used to preprocess, filter, enhance, and extract features from the captured images to reduce noise, improve image quality, and extract target information. These operations typically rely on specialized image processing software or algorithms, which requires advanced image processing skills. Such instruments are bulky, poorly portable, and expensive, making them generally unsuitable for home use. Specifically, their shortcomings are mainly reflected in:

[0004] 1. The electrochemical reaction excitation unit of traditional ECL detectors is usually controlled by manually adjusting the resistor or knob to control the excitation voltage. The process is cumbersome and the excitation voltage is often difficult to control precisely, which causes errors in each test due to different excitation voltages.

[0005] 2. Traditional ECL detectors obtain test results by capturing images with a camera, extracting video frames, and performing complex calculations. This requires the use of devices such as computers, mobile phones, and Raspberry Pis for data processing, which increases the cost and size of the detector.

[0006] 3. Traditional ECL testers require an external 220V AC power supply or a special transformer to convert to the required DC voltage, resulting in poor portability and versatility.

[0007] 4. For traditional ECL detectors, the amount of image analysis data is large, and it takes tens of seconds or even minutes from the start to the end of the detection, making the operation cumbersome.

[0008] 5. Traditional ECL testing instruments require a built-in camera, which makes the instrument bulky and unable to be carried around or used handheld.

[0009] In recent years, photodiodes have been widely used in various sensing systems, perhaps due to their advantages such as low cost, high sensitivity, fast response, and miniaturization. Integrating photodiodes into ECL detection systems can not only significantly reduce system complexity and cost but also improve detection speed, providing a new solution for achieving fully automated immunoassay ECL detection.

[0010] Nevertheless, designing an efficient and reliable fully automated ECL detector based on photodiodes and ensuring its good performance in practical immunoassay applications remains a significant challenge. Utility Model Content

[0011] The technical problem to be solved by this utility model is to address the shortcomings of the existing technology and to provide an ECL detector that is simple in structure, easy to operate and cost-effective, in order to meet the growing needs of clinical diagnosis and home self-testing.

[0012] The fully automatic electrochemiluminescence detector based on photodiodes of this invention includes a housing, in which a light signal acquisition module, a small-package circuit board, an ECL chip, a human-machine interface module, and a chip input / output device are disposed. The small-package circuit board contains a photocurrent detection unit, an electrochemical reaction excitation unit, a microcontroller, and a power supply module. The human-machine interface module is electrically connected to the input terminal of the microcontroller, and the output terminal of the microcontroller is electrically connected to the input terminal of the electrochemical reaction excitation unit. The output terminal of the electrochemical reaction excitation unit is electrically connected to the ECL chip through the chip input / output device. The ECL chip contains a test strip sample pad, a detection pad, and a connecting pad. The acquisition terminal of the photocurrent detection unit is positioned to match the detection pad, and the output terminal of the photocurrent detection unit is electrically connected to the signal acquisition terminal of the microcontroller. The power supply module serves as a power source for powering the power-consuming modules in the detector, and the power supply module has a USB power supply interface and a battery power supply interface.

[0013] Preferably, the electrochemical reaction excitation unit includes a non-inverting amplifier circuit, a voltage regulator circuit, a DAC circuit, and a reference voltage circuit; the voltage regulator circuit is connected to the power input terminal of the non-inverting amplifier circuit; the reference voltage circuit is connected to the power input terminal of the DAC circuit; the DAC circuit receives the excitation voltage parameters and outputs an output voltage; the non-inverting amplifier circuit amplifies the output voltage of the DAC circuit and uses the amplified voltage as the excitation voltage.

[0014] Preferably, the chip in / out device includes a front spring, an elastic contact, a guide rail, and a rear baffle. The guide rail is fixed to the bottom of the housing, and one end of the housing has an ECL chip inlet / outlet. The ECL chip is inserted into the ECL chip inlet / outlet and is slidably mounted on the guide rail. A front spring is installed in the housing at the end of the guide rail, and the end of the front spring is connected to the ECL chip. An elastic contact is also installed in the housing, and the elastic contact is connected to the output end of the electrochemical reaction excitation unit through a wire. The ECL chip has a conductor that contacts the elastic contact. A rear baffle for locking the ECL chip is slidably installed at the end of the housing away from the front spring.

[0015] Preferably, the optical signal acquisition module includes a photodiode and a light-shielding box; the light-shielding box is fixed in the housing, the bottom of the light-shielding box is open, and the bottom of the light-shielding box is directly opposite the reaction area on the detection pad of the ECL chip; the photodiode is installed in the light-shielding box and is used to acquire the photoelectric signal generated by the ECL reaction.

[0016] Preferably, the photocurrent detection unit includes a transimpedance amplifier circuit, an inverting amplifier circuit, a non-inverting amplifier circuit, an active filter circuit, and an ADC circuit; the photodiode amplifies the collected photoelectric signal sequentially through the transimpedance amplifier circuit, the inverting amplifier circuit, and the non-inverting amplifier circuit, then filters it through the active filter circuit to remove high-frequency noise, and finally samples and quantizes it into a digital signal through the ADC circuit before transmitting it to the microcontroller.

[0017] Preferably, the housing includes a top cover and a base; the lower end of the top cover is provided with four protruding pins, which are respectively inserted into the four corners of the small package circuit board; the base is provided with four hollow pillars, which correspond one-to-one with the four pins, so that when the top cover and the base are closed, the hollow pillars and the pins form a hole-shaft fit.

[0018] Preferably, the light-shielding box, the top cover, and the base are all made of black polylactic acid (PLA) material.

[0019] Preferably, the human-computer interaction module includes a start button, a search button, a settings button, a power switch, and a display screen, all of which are embedded in the upper cover.

[0020] Preferably, the small packaged circuit board also includes a memory, which is electrically connected to the microcontroller.

[0021] Preferably, the small packaged circuit board is further provided with a serial port chip, one end of which is electrically connected to the microcontroller, and the other end of which communicates with external devices through an external interface.

[0022] Beneficial effects

[0023] The advantages of this utility model are:

[0024] 1. The photodiode used in this invention can respond quickly to changes in light intensity, with a response time typically in the nanosecond to microsecond range, which is much faster than the frame capture speed of a camera. This is especially important for real-time monitoring or applications that require rapid response.

[0025] 2. Compared with instruments that use cameras, the detector of this utility model requires less signal data to be processed, which reduces the need and complexity of subsequent data processing and makes the system easier to automate; it only takes a few seconds from clicking the start button to displaying the detection results.

[0026] 3. The detector of the present invention has a built-in power module, which is equipped with a USB power supply interface and a battery power supply interface. It can be powered by USB and is compatible with common mobile phone power adapters. It also has a built-in lithium battery, which can be used to power the instrument without an external power source, thus increasing the portability and versatility of the instrument.

[0027] 4. This invention significantly reduces the cost of the detector by using a photodiode as the photosensitive element. Compared to a camera, photodiodes have lower hardware costs and do not require complex image processing software, making them suitable for home use.

[0028] 5. This utility model, through the design of a small packaged circuit board and a compact shell structure, makes the detector small in size, easy to use handheld and carry. Attached Figure Description

[0029] Figure 1 This is a half-sectional view of the fully automatic electrochemiluminescence detector based on a photodiode according to this utility model.

[0030] Figure 2 This is a bottom view of the top cover structure of the fully automatic electrochemiluminescence detector based on a photodiode according to this utility model.

[0031] Figure 3 This is a schematic diagram of the power module boost circuit of this utility model.

[0032] Figure 4 This is a schematic diagram of the charging circuit for the power module of this utility model.

[0033] Figure 5 This is a schematic diagram of the linear voltage regulator circuit for the power module of this utility model.

[0034] Figure 6 This is a schematic diagram of the boost circuit of the electrochemical excitation unit of this utility model.

[0035] Figure 7 This is a schematic diagram of the voltage output circuit of the electrochemical excitation unit of this utility model.

[0036] Figure 8 This is a circuit diagram of the photocurrent detection module of this utility model.

[0037] Figure 9 This is a circuit diagram of the active filter circuit of this utility model.

[0038] Figure 10 This is the circuit schematic diagram of the ADC circuit of this utility model.

[0039] Figure 11 This is a schematic diagram of the microcontroller and its peripheral circuits of this utility model.

[0040] Figure 12 This is a circuit diagram of the memory circuit of this utility model.

[0041] Figure 13 This is a circuit diagram of the serial communication circuit of this utility model.

[0042] Figure 14 This is a graph showing the detection results of the detector of this invention when detecting luteinizing hormone (LH).

[0043] The components include: photodiode 11; light shield 12; circuit board 2; photocurrent detection unit 21; electrochemical reaction excitation unit 22; microcontroller 23; power module 24; memory chip 25; serial communication chip 26; ECL chip 3; test strip sample pad 31; detection pad 32; connection pad 33; start button 41; lookup button 42; setting button 43; power switch 44; display screen 45; top cover 51; base 52; pin 53; hollow column 54; front spring 61; elastic contact 62; guide rail 63; and rear baffle 64. Detailed Implementation

[0044] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0045] See Figures 1-2This utility model discloses a fully automatic electrochemiluminescence detector based on a photodiode, comprising a light signal acquisition module 1, a small-package circuit board 2, an ECL chip 3, a human-machine interface module 4, a housing 5, and a chip loading / unloading device 6. The light signal acquisition module 1 includes a photodiode 11 and a light-shielding box 12; the small-package circuit board 2 includes a photocurrent detection unit 21, an electrochemical reaction excitation unit 22, a microcontroller 23, a power module 24, a memory 25, and a serial port chip 26; the human-machine interface module 4 includes a start button 41, a lookup button 42, a setting button 43, a power switch 44, and a display screen 45; the housing 5 includes a top cover 51 and a base 52; and the chip loading / unloading device 6 consists of a front spring 61, an elastic contact 62, a guide rail 63, and a rear baffle 64.

[0046] ECL chip 3 is inserted into and fixed inside the detector through chip entry / exit device 6 inside housing 5; power module 24 supplies power to the detector; after turning on power switch 44, click start button 41 on human-machine interaction module 4 to start the fully automatic detection process, and the detection result is automatically displayed on display screen 45.

[0047] Specifically, after clicking the start button 41, the microcontroller 23 first sends the set excitation voltage parameters to the digital-to-analog converter (DAC) chip in the electrochemical reaction excitation unit 22 via the serial peripheral interface (SPI). After receiving the instruction from the microcontroller 23, the DAC chip outputs the specified voltage. This voltage is amplified by the amplifier circuit to become the excitation voltage. The excitation voltage supplies power to the driving electrode on the ECL chip 3 through the wire between the chip input / output device 6 and the amplifier circuit and the elastic contact 62 thereon, thereby triggering the ECL reaction. The photodiode 11 in the optical signal acquisition module 1 receives the ECL signal, converts it into a photoelectric signal, and transmits it to the photocurrent detection unit 21 through the wire. The photoelectric signal is converted into a corresponding voltage signal by the transimpedance amplifier circuit in the photocurrent detection unit 21. The voltage signal passes through the inverting amplifier circuit, the non-inverting amplifier circuit, and the filtering circuit in the photocurrent detection unit 21 in sequence. The filtered voltage signal is quantized into a digital signal by the analog-to-digital converter (ADC) chip and then sent to the microcontroller 23 for digital filtering processing via the bidirectional two-wire synchronous serial bus (I2C) protocol. The peak value of the processed signal is calculated and sent to the display screen 45 via SPI communication. The display screen 45 refreshes and displays the currently received data in real time. Once the displayed data is stable, it is the detection result. The microcontroller 23 stores the detection result in the memory 25, and one fully automatic detection process ends.

[0048] The following will provide a detailed description of each component that makes up this testing instrument.

[0049] Regarding the power module 24, it can be powered by an external 5V power supply via a USB interface, or it can be powered by a battery. The power module 24 has a switching circuit that switches to battery power when no 5V power supply is connected. When powered by a battery, the power module 24 boosts and regulates the input voltage to 5V. When an external 5V power supply is connected, the lithium battery charging management chip charges the battery. The linear regulator steps down the 5V output voltage of the power module 24 to 3.3V to power the microcontroller 23.

[0050] Specifically, please refer to Figure 3 , Figure 4 and Figure 5 The power module 24 mainly consists of three parts. In this module, the boost chip is TPS61023, and the power module 24 includes a 10μF and a 4.7μF surface mount capacitor, a 732kΩ and a 100kΩ surface mount resistor, and a 2.2μH surface mount capacitor; the lithium battery charging management chip is TP4057, and its circuit includes two 10μF surface mount capacitors and a 2kΩ surface mount resistor; the linear regulator chip is AMS1117-3.3, and its circuit includes two 22μF surface mount capacitors and two 100nF surface mount capacitors.

[0051] The electrochemical reaction excitation unit 22 includes a non-inverting amplifier circuit, a boost circuit, a DAC circuit, and a reference voltage circuit. The boost circuit boosts the 5V supplied by the power module 24 to 24V to power the operational amplifier in the non-inverting amplifier circuit. The reference voltage circuit provides a 4.096V reference voltage to the DAC circuit, which provides a programmable output voltage from 0V to 4.096V. The non-inverting amplifier circuit amplifies the output voltage of the DAC circuit, achieving a programmable excitation voltage output from 0-22V.

[0052] Specifically, please refer to Figure 6 The BOOST boost circuit uses the TPS61175 chip and includes one 10μF surface-mount capacitor, two 47nF surface-mount capacitors, two 4.7μF surface-mount capacitors, one 3.16kΩ surface-mount resistor, one 16.2kΩ surface-mount resistor, one 300kΩ surface-mount resistor, one 121kΩ surface-mount resistor, one 15μH surface-mount inductor, and one SS54 diode. Figure 7As shown, the reference voltage circuit consists of three parts. The front-end chip used is REF5040, and its peripheral circuit includes two 1μF surface mount capacitors and one 22μF surface mount capacitor. The DAC circuit uses a DAC7311 chip, which includes two 22Ω surface mount resistors as the series resistors for SPI, one 100nF surface mount capacitor, and one 10μF surface mount capacitor. The non-inverting amplifier circuit uses an LM2094 operational amplifier, and the amplifier circuit includes one 100nF surface mount capacitor, one 8.2kΩ surface mount resistor, one 10kΩ surface mount resistor, and one 40kΩ surface mount resistor.

[0053] The photocurrent detection unit 21 includes a transimpedance amplifier circuit, an inverting amplifier circuit, a non-inverting amplifier circuit, an active filter circuit, and an ADC circuit. The photocurrent generated by the photodiode 11 is amplified sequentially by the transimpedance amplifier circuit, the inverting amplifier circuit, and the non-inverting amplifier circuit. Then, it is filtered by the active filter circuit to remove high-frequency noise. Finally, it is sampled and quantized into a digital signal by the ADC circuit and transmitted to the microcontroller 23.

[0054] Since the detection pad 32 on the ECL chip 3 in this embodiment has two reaction areas, it is necessary to set up two channels of amplification circuit and active filter circuit in the photocurrent detection unit 21, specifically as follows: Figure 8 and Figure 9 As shown. Figure 8 The diagram shows the circuit schematic of a two-channel amplifier circuit. The amplifier circuit uses a multi-stage AD866X series operational amplifier. The transimpedance amplifier circuit uses a single-channel AD8661 chip, while the inverting and non-inverting amplifier circuits each use one channel of a dual-channel AD8662 chip. The amplifier circuit also includes two 100nF surface-mount capacitors, three 8pF surface-mount capacitors, two 10kΩ surface-mount resistors, three 1kΩ surface-mount resistors, one 20kΩ surface-mount resistor, and one 51kΩ surface-mount resistor. Figure 9 As shown, the active filter circuit uses the AD8656 chip as the operational amplifier chip, and includes one 2.37kΩ surface mount resistor, one 4.87kΩ surface mount resistor, one 1.58kΩ surface mount resistor, two 100nF surface mount capacitors, and one 22nF surface mount capacitor. The above amplifier circuit and active filter circuit are configured for one photocurrent detection channel; the other channel has the same configuration and will not be described further. Figure 10 As shown, the ADC circuit uses the ADS1115 chip, which includes two 10kΩ pull-up resistors and one 100nF surface-mount capacitor.

[0055] Please see Figure 11The microcontroller 23 uses a 32-bit microcontroller chip, specifically the STM32L431 chip. Its peripheral circuitry includes a power supply circuit, a reset circuit, a crystal oscillator circuit, a debug interface circuit, and a startup circuit. The power supply circuit provides 3.3V from a linear regulator and connects to the microcontroller's VDD pin. The reset circuit consists of a 10kΩ surface-mount resistor and a 1μF surface-mount capacitor, providing a reset function for the microcontroller 23. The crystal oscillator circuit uses an 8MHz crystal to provide the clock for the microcontroller 23, with a 20pF load capacitor connected in parallel to each of the crystal's two pins. The debug interface circuit uses a 1*4P header for debugging and programming the program. The startup circuit uses BOOT0 connected in series with a 510Ω resistor and then grounded as the default startup circuit.

[0056] The microcontroller 23 is connected to the memory 25 and also to one end of the serial port chip 26. The other end of the serial port chip 26 is connected to the USB interface, so that the detector of this invention can communicate with external devices that support USB (such as computers and mobile phones) through the serial port chip 26 to achieve bidirectional data transmission.

[0057] Specifically, please refer to Figure 12 The memory 25 uses an AD24C02 chip, which communicates with the microcontroller 23 via I2C for data storage. Its peripheral circuitry includes two 10kΩ pull-up resistors. Figure 13 As shown, the serial port chip 26 uses CH340N, and its peripheral circuit includes two 100nF surface mount capacitors.

[0058] like Figure 1 As shown, in the human-computer interaction module 4, the start button 41, query button 42, setting button 43, power switch 44, and display screen 45 are all embedded in the upper cover 51. The display screen 45 is 1.8 inches in size and communicates with the microcontroller 23 via the SPI protocol. The start button 41 is connected to the GPIO port of the microcontroller 23 after passing through a debouncing circuit composed of a 100nF surface-mount capacitor and a 10kΩ surface-mount resistor. The detection process is started by pressing the start button 41, the historical records are queried by pressing the query button 42, and the excitation voltage level pre-stored in the memory 25 is selected by pressing the setting button 43.

[0059] The front spring 61, elastic contact 62, and guide rail 63 of the chip entry / exit device 6 are located on the base 52. The front spring 61 and rear baffle 64 are used to fix the ECL chip 3 to a designated position, so that the light-shielding box 12 and the two photodiodes 11 are respectively facing the observation window of the ECL chip 3. Specifically, one end of the housing 5 has an ECL chip inlet / outlet, into which the ECL chip 3 is inserted and slidably mounted on the guide rail 63. The front spring 61 is installed in the housing 5 at the end of the guide rail 63, with its end connected to the ECL chip 3. The housing 5 also has an elastic contact 62 installed, which is connected to the output terminal of the DAC circuit via a wire. The ECL chip 3 has a conductor that contacts the elastic contact 62. The rear baffle 64, used to lock the ECL chip 3, is slidably mounted at the end of the housing 5 away from the front spring 61.

[0060] After the rear end baffle 64 is pushed upward, the ECL chip 3 can be inserted into the designated position along the guide rail 63, so that the elastic contact 62 is connected to the driving electrode of the ECL chip 3; when the ECL chip 3 is removed, the rear end baffle 64 is pushed upward, and the ECL chip 3 will automatically pop out under the tension of the front end spring 61.

[0061] Please see Figure 2 The upper cover 51 has four protruding pins 53 at its lower end for fixing the small packaged circuit board 2; the base 52 has four hollow pillars 54, which correspond to the pins 53 of the upper cover 51; when the upper cover 51 and the base 52 are closed, the hollow pillars 54 and the pins 53 form a hole-shaft fit, and the upper and lower covers are fixed by a certain method (such as glue bonding or ultrasonic bonding process). In addition, the inner side of the base 52 has a groove, and the photodiode 11 is fixed on the light shielding box 12, which is installed on the groove inside the base 52.

[0062] In this embodiment, the housing 5, the light-shielding box 12, and the rear baffle 64 are all made of black polylactic acid (PLA) material. The dimensions of the housing 5 are 90mm*50mm*30mm.

[0063] The following describes the application method of a fully automated electrochemiluminescence detector based on a photodiode in the detection process of luteinizing hormone (LH).

[0064] First, add 30 μL of sample solution containing LH to the sample pad 31 of the test strip and wait 3 minutes for the immune reaction to occur.

[0065] Next, add 30 μL of PBS to sample pad 31 of the test strip to wash away any excess residue for 3 minutes; then add 20 μL of PBS to connection pad 33.

[0066] Finally, the ECL chip 3 is placed in a fully automated electrochemiluminescence detector based on a photodiode for detection. The power switch 44 is turned on, and the start button 41 is pressed to begin detection. The electrochemical reaction excitation unit 22 outputs a default 11V excitation voltage to induce the ECL reaction on the detection pad 32. During the reaction, the ECL signals on the T and C lines of the detection pad 32 are collected by the photodiode 11 and converted into photocurrent signals. These signals pass through an amplification circuit, a filtering circuit, and an ADC, and are finally processed by the microcontroller 23. The peak values ​​of the T and C lines are then output to the display screen 45. The ratio of the collected signal values ​​(T / C) is used to quantitatively detect LH.

[0067] Now containing 0 mIU mL -1 0.1 mIU mL -1 1 mIU mL -1 and 10 mIU mL -1 Using the LH test sample solution and the detector of this invention as examples, we tested the relationship between the concentration of LH in the sample solution and the T / C ratio, as well as the effectiveness of the detector in immunoassay. The test results are as follows: Figure 14 As shown in the results, the detection results indicate that, using the fully automated electrochemiluminescence detector based on photodiodes of this invention, the T / C ratio on ECL chip 3 increases with increasing LH concentration; and within the range of 0.1-10 mIU / mL... -1 Within the specified range, there is a good linear relationship between the logarithm of LH concentration and the logarithm of T / C, with a linear fitting equation of Y = 0.387X + 0.181 and a correlation coefficient R0. 2 =0.9009 (n=5). Therefore, the fully automated electrochemiluminescence detector based on photodiode of this invention can be applied to LH immunoassay, and can also be applied to the immunoassay of biomarkers for other diseases and other physiological activities.

[0068] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present utility model. These modifications and improvements will not affect the effectiveness of the present utility model or the practicality of the patent.

Claims

1. A fully automated electrochemiluminescence detector based on photodiodes, characterized in that, The device includes a housing (5), which contains a light signal acquisition module (1), a small package circuit board (2), an ECL chip (3), a human-machine interaction module (4), and a chip entry / exit device (6). The small package circuit board (2) contains a photocurrent detection unit (21), an electrochemical reaction excitation unit (22), a microcontroller (23), and a power supply module (24). The human-machine interaction module (4) is electrically connected to the input terminal of the microcontroller (23), and the output terminal of the microcontroller (23) is electrically connected to the input terminal of the electrochemical reaction excitation unit (22). The output end of the unit (22) is electrically connected to the ECL chip (3) through the chip input / output device (6). The ECL chip (3) is provided with a test strip sample pad (31), a detection pad (32) and a connecting pad (33). The acquisition end of the photocurrent detection unit (21) is adapted to the position of the detection pad (32). The output end of the photocurrent detection unit (21) is electrically connected to the signal acquisition end of the microcontroller (23). The power module (24) is used as a power supply to power the power modules in the detector. The power module (24) is provided with a USB power supply interface and a battery power supply interface.

2. The fully automated electrochemiluminescence detector based on a photodiode according to claim 1, characterized in that, The electrochemical reaction excitation unit (22) includes a non-inverting amplifier circuit, a voltage regulator circuit, a DAC circuit, and a reference voltage circuit; the voltage regulator circuit is connected to the power input terminal of the non-inverting amplifier circuit; the reference voltage circuit is connected to the power input terminal of the DAC circuit; the DAC circuit receives the excitation voltage parameters and outputs an output voltage; the non-inverting amplifier circuit amplifies the output voltage of the DAC circuit and uses the amplified voltage as the excitation voltage.

3. The fully automated electrochemiluminescence detector based on a photodiode according to claim 2, characterized in that, The chip in / out device (6) includes a front spring (61), an elastic contact (62), a guide rail (63), and a rear baffle (64). The guide rail (63) is fixed to the bottom of the housing (5). One end of the housing (5) is provided with an ECL chip inlet / outlet. The ECL chip (3) is inserted into the ECL chip inlet / outlet and is slidably mounted on the guide rail (63). The front spring (61) is installed in the housing (5) at the end of the guide rail (63). The end of the front spring (61) is connected to the ECL chip (3). The housing (5) is also provided with an elastic contact (62). The elastic contact (62) is connected to the output end of the electrochemical reaction excitation unit (22) through a wire. The ECL chip (3) is provided with a conductor that contacts the elastic contact (62). The end of the housing (5) away from the front spring (61) is slidably mounted with a rear baffle (64) for locking the ECL chip (3).

4. The fully automated electrochemiluminescence detector based on a photodiode according to claim 1, characterized in that, The optical signal acquisition module (1) includes a photodiode (11) and a light shield (12); the light shield (12) is fixed in the housing (5), the bottom of the light shield (12) is open, and the bottom of the light shield (12) is directly opposite the reaction area on the detection pad (32) of the ECL chip (3); the photodiode (11) is installed in the light shield (12) and is used to acquire the photoelectric signal generated by the ECL reaction.

5. The fully automated electrochemiluminescence detector based on a photodiode according to claim 4, characterized in that, The photocurrent detection unit (21) includes a transimpedance amplifier circuit, an inverting amplifier circuit, a non-inverting amplifier circuit, an active filter circuit, and an ADC circuit. The photodiode (11) amplifies the collected photoelectric signal through the transimpedance amplifier circuit, the inverting amplifier circuit, and the non-inverting amplifier circuit in sequence. Then, it filters the signal through the active filter circuit to remove high-frequency noise. Finally, it is sampled and quantized into a digital signal by the ADC circuit and transmitted to the microcontroller (23).

6. The fully automated electrochemiluminescence detector based on a photodiode according to claim 4, characterized in that, The housing (5) includes a top cover (51) and a base (52); the lower end of the top cover (51) is provided with four protruding pins (53), and the four pins (53) are respectively inserted into the four corners of the small package circuit board (2); the base (52) is provided with four hollow pillars (54), and the four hollow pillars (54) correspond one-to-one with the four pins (53) so that when the top cover (51) and the base (52) are closed, the hollow pillars (54) and the pins (53) form a hole-shaft fit.

7. The fully automated electrochemiluminescence detector based on a photodiode according to claim 6, characterized in that, The light-shielding box (12), the top cover (51) and the base (52) are all made of black polylactic acid material.

8. The fully automated electrochemiluminescence detector based on a photodiode according to claim 6, characterized in that, The human-computer interaction module (4) includes a start button (41), a lookup button (42), a settings button (43), a power switch (44), and a display screen (45). The start button (41), the lookup button (42), the settings button (43), the power switch (44), and the display screen (45) are all embedded in the upper cover (51).

9. The fully automated electrochemiluminescence detector based on a photodiode according to claim 1, characterized in that, The small packaged circuit board (2) is also provided with a memory (25), which is electrically connected to the microcontroller (23).

10. The fully automated electrochemiluminescence detector based on a photodiode according to claim 1, characterized in that, The small packaged circuit board (2) is also provided with a serial port chip (26). One end of the serial port chip (26) is electrically connected to the microcontroller (23), and the other end of the serial port chip (26) communicates with external devices through an external interface.

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