LED light source capable of outputting stable power for PMT photon counting evaluation and control method thereof

Abstract

The present invention provides an LED light source capable of outputting stable power for PMT photon counting evaluation and a control method thereof. The LED light source includes an LED light source circuit, a light-shielding structure, and a light-emitting structure. The LED light source circuit is composed of an LED light-emitting diode, a power regulating subcircuit, and a light-emitting stabilization regulating subcircuit. The power regulating subcircuit can adjust the light source power by adjusting the resistance value of an adjustable resistor. The light-emitting stabilization regulating subcircuit cooperates with the power regulating subcircuit to control the entire circuit to reach a balanced state. The LED light source capable of outputting stable power for PMT photon counting evaluation according to the present invention can output stable power. When the LED light source circuit outputs full power, the light source can maintain continuous output for more than 200 hours, and is used to realize consistency detection of the counting sensitivity of a PMT photon counting module.

Description

Technical Field

[0001] The present invention relates to the technical field of PMT photon counters, in particular to a test system for a PMT photon counter, and more particularly to an LED light source capable of outputting stable power for PMT photon counting evaluation and a control method thereof. Background Art

[0002] PMT photon counting modules are widely used in fields such as chemiluminescence and immunoassays. PMT photon counting modules are generally composed of photomultiplier tubes and back-end electronic components. Their counting sensitivity is a key indicator for evaluating PMT photon counting modules and directly affects the accuracy of detection instruments such as chemiluminescence immunoassay analyzers. Because current production processes make it difficult to ensure that the counting sensitivity of each PMT photon counting module is completely consistent, the counting sensitivity between individual PMT photon counting modules varies greatly, resulting in some deviation in the number of photons output by different PMT photon counting modules for light of the same intensity. Therefore, it is necessary to adjust the sensitivity of multiple groups of PMT photon counting modules to achieve high consistency in order to reduce the deviation in the test values ​​of each detection instrument.

[0003] The light source used in existing test devices for evaluating the counting sensitivity of PMT photon counting modules has poor stability, resulting in large errors in the measured counting sensitivity of the PMT photon counting modules. In order to make the counting sensitivity of each tested product as accurate as possible in terms of numerical value, to achieve high consistency between batches of products or for calibration purposes in certain specific scenarios, it is necessary to provide an LED light source module that can output stable power to ensure the stability and accuracy of PMT photon counting evaluation. Summary of the Invention

[0004] In view of the defects and shortcomings of the existing LED light sources used for photon counting evaluation, the present invention aims to provide an LED light source that can output stable power for PMT photon counting evaluation, including an LED light source circuit, a light shielding and light output structure;

[0005] The LED light source circuit includes an LED light emitting diode, a power regulation subcircuit and a light emitting stabilization regulation subcircuit;

[0006] The LED light emitting diode is arranged at the output end of the power regulating subcircuit, and the output power of the LED light emitting diode is controlled and regulated by the power regulating subcircuit;

[0007] The light emitting stabilization regulating subcircuit is connected to the power regulating subcircuit and is used to feed back the changes in the luminous intensity of the LED light emitting diode collected in real time to the power regulating subcircuit via a negative feedback circuit, so that the output of the power regulating subcircuit remains stable, thereby regulating the stable luminous power of the LED light source circuit;

[0008] The light-shielding and light-emitting structures are both arranged on the LED light source PCB circuit board, and the light-shielding and light-emitting structures are set at the position of the LED light source circuit corresponding to the LED light-emitting diode; wherein, a light-shielding groove is set on one side surface of the light-shielding and light-emitting structure, and the LED light-emitting diode is accommodated in the light-shielding groove, and a through microhole is opened in the light-shielding groove at a position directly in front of the LED light-emitting diode as a light-emitting hole; a circular groove is set on the other side surface of the light-shielding and light-emitting structure, and the circular groove takes the light-emitting hole as the center of the circle; a diffuser with a shape and depth adapted to the circular groove is arranged in the circular groove, which is used to evenly diffuse the light output through the light-emitting hole and widen the luminous surface of the light source.

[0009] In a further embodiment, the power regulation subcircuit includes a first operational amplifier U1, a first resistor R1, a second resistor R2, an adjustable resistor VR1, a first capacitor C1, and a voltage reference chip U2;

[0010] The output end of the voltage reference chip U2 is first connected in series with the first resistor R1, and then connected to the tap end and one end of the adjustable resistor VR1, and the other end of the adjustable resistor VR1 is grounded; the output end of the voltage reference chip U2 is also connected to the reference voltage V REF ;

[0011] A second resistor R2 is connected in series to the node where the first resistor R1 and the adjustable resistor VR1 are connected in series, and then connected to the non-inverting input terminal of the first operational amplifier U1;

[0012] A first capacitor C1 is connected between the inverting input terminal and the output terminal of the first operational amplifier U1;

[0013] The output end of the first operational amplifier U1 is connected to one end of the LED light emitting diode D1 , and the other end of the LED light emitting diode D1 is connected to a power supply circuit, and is powered by the power supply circuit.

[0014] In a further embodiment, by adjusting the resistance of the adjustable resistor VR1, the resistance of the equivalent resistor in the power regulation sub-circuit chain changes, thereby adjusting the voltage value of the non-inverting input terminal of the first operational amplifier U1, thereby changing the voltage value of the inverting input terminal of the first operational amplifier U1. The change in the voltage value of the inverting input terminal further changes the voltage value U of the output terminal of the first operational amplifier U1 through the first capacitor C1 connected across the inverting input terminal and the output terminal. OUT , thereby adjusting the change in the output power of the LED light emitting diode.

[0015] In a further embodiment, the light emitting stabilization control sub-circuit includes a second operational amplifier U3, a photodiode PD1, a second capacitor C2, a third resistor R3 and a fourth resistor R4;

[0016] The photodiode PD1 is located at the inverting and non-inverting input terminals of the second operational amplifier U3; the positive electrode of the photodiode PD1 is connected to the non-inverting input terminal of the second operational amplifier U3 and is grounded, the negative electrode of the photodiode PD1 is connected to the inverting input terminal of the second operational amplifier U3, and the inverting input terminal and the output terminal are connected via a third resistor R3 to form a negative feedback circuit;

[0017] The output terminal of the second operational amplifier U3 is connected to the inverting input terminal of the first operational amplifier U1 in the power regulation sub-circuit through the fourth resistor R4; in a dark environment, the voltage across the photodiode PD1 is forced to be 0V;

[0018] Through the light-shielding treatment of the light-shielding and light-emitting structures, the light emitted by the LED D1 in the power regulation subcircuit hits the photodiode PD1, generating a current from the anode to the cathode, which is manifested as an increase in the output voltage of the second operational amplifier U3;

[0019] The flow of electrons and holes in the photodiode PD1 controlled by light on its PN junction causes current to be conducted from the cathode to the anode of the diode, wherein the current output by the photodiode PD1 increases as the brightness of the LED light emitting diode D1 increases.

[0020] In a further embodiment, the current of the photodiode PD1 changes with the light emitted by the collected LED light-emitting diode D1, and the change is fed back to the inverting input terminal of the first operational amplifier U1 of the power regulation sub-circuit through a negative feedback circuit, so that the positive and inverting input terminal voltages of the first operational amplifier U1 remain equal, thereby achieving the function of stabilizing the luminous power of the LED light-emitting diode.

[0021] In a further embodiment, the light-shielding and light-emitting structures are respectively dug out with grooves of corresponding heights according to the heights of the photodiode PD1 and the LED light-emitting diode D1, so as to seamlessly fit onto the PCB circuit board without being interfered with by the heights of the photodiode PD1 and the LED light-emitting diode D1, thereby achieving a light-shielding effect.

[0022] According to a second aspect of the present invention, a method for controlling an LED light source capable of outputting stable power for PMT photon counting evaluation is also provided, the method comprising the following steps:

[0023] Adjust the resistance of the variable resistor VR1 so that the resistance of the variable resistor VR1 becomes larger, and the voltage division obtained thereby increases, further increasing the voltage Ui+ of the non-inverting input terminal of the first operational amplifier U1. Since the voltages of the positive and negative input terminals of the first operational amplifier U1 remain equal, the voltage Ui- of the negative input terminal increases, and the voltage Ui- of the output terminal of the first operational amplifier U1 increases.OUT As it increases, the output power of the LED light-emitting diode D1 increases and the light becomes stronger;

[0024] As the output power of LED D1 increases and the light becomes stronger, the photodiode PD1 receives the enhanced light, and the current ipd flowing on the PN junction increases, and the U of the second operational amplifier U3 increases. OUT The voltage is increased and fed back to the inverting input terminal Ui- of the first operational amplifier U1, and increases until the LED D1 emits light stably and the entire circuit reaches a balanced state.

[0025] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below, as long as such concepts are not mutually inconsistent, can be considered part of the inventive subject matter of this disclosure. In addition, all combinations of the claimed subject matter are considered part of the inventive subject matter of this disclosure.

[0026] The foregoing and other aspects, embodiments, and features of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the present invention, such as features and / or beneficial effects of the exemplary embodiments, will become apparent from the following description or through practice of specific embodiments according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are not intended to be drawn to scale. In the accompanying drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings.

[0028] Figure 1 4 is a circuit schematic diagram of an LED light source circuit capable of outputting stable power for PMT photon counting evaluation according to an embodiment of the present invention.

[0029] Figure 2 4 is a circuit schematic diagram of a power regulation sub-circuit according to an embodiment of the present invention.

[0030] Figure 3 4 is a circuit schematic diagram of a sub-circuit for regulating and stabilizing light emission according to an embodiment of the present invention.

[0031] Figure 4A 、 4B They are schematic diagrams of light-shielding and light-emitting structures according to embodiments of the present invention.

[0032] Figure 5 3 is a test schematic diagram of an LED light source capable of outputting stable power for PMT photon counting evaluation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to better understand the technical content of the present invention, specific embodiments are given below in conjunction with the accompanying drawings.

[0034] Various aspects of the present invention are described in this disclosure with reference to the accompanying drawings, in which a number of illustrative embodiments are shown. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present invention. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed herein are not limited to any embodiment. In addition, some aspects of the present disclosure may be used alone or in any appropriate combination with other aspects disclosed herein.

[0035] {Example 1}

[0036] Combine Figure 1 、 2 , 3 and Figure 4A 、 4B As shown, the LED light source capable of outputting stable power for PMT photon counting evaluation according to an embodiment of the present invention includes an LED light source circuit, a light-shielding structure, and a light-emitting structure.

[0037] like Figure 1 The LED light source circuit shown includes an LED light emitting diode 100 , a power regulation subcircuit 200 , and a light emitting stabilization control subcircuit 300 .

[0038] The LED light emitting diode 100 is provided at the output end of the power regulating sub-circuit 200 , and the output power of the LED light emitting diode 100 is controlled and regulated by the power regulating sub-circuit 200 .

[0039] The light emitting stability regulating sub-circuit 300 is connected to the power regulating sub-circuit 200, and is used to feed back the changes in the light emitting intensity of the LED light emitting diode collected in real time to the power regulating sub-circuit via a negative feedback circuit, so that the output of the power regulating sub-circuit remains stable, thereby regulating the stable light emitting power of the LED light source circuit.

[0040] The light-shielding and light-emitting structures 400 are both arranged on the PCB circuit board of the LED light source, and the light-shielding and light-emitting structures are set at the position of the LED light source circuit corresponding to the LED light-emitting diode; wherein, a light-shielding groove is set on one side surface of the light-shielding and light-emitting structure, and the LED light-emitting diode is accommodated in the light-shielding groove, and a through microhole is opened in the light-shielding groove at a position directly in front of the LED light-emitting diode as a light-emitting hole; a circular groove is set on the other side surface of the light-shielding and light-emitting structure, and the circular groove takes the light-emitting hole as the center of the circle; a diffuser sheet adapted to its shape and depth is arranged in the circular groove, which is used to evenly diffuse the light output through the light-emitting hole and widen the luminous surface of the light source.

[0041] It should be understood that, with the PCB circuit board as the carrier, the aforementioned power regulation subcircuit 200 and the light emitting stabilization control subcircuit 300 are arranged on the PCB circuit board in the form of a printed circuit, and the LED light emitting diode is soldered between the output end of the power regulation subcircuit 200 and the power supply circuit in an appropriate manner. The power is supplied by the power supply circuit, and the power regulation subcircuit 200 adjusts the light emitting power, and controls the light emitting stabilization by controlling the light emitting stabilization subcircuit 300, so as to achieve continuous and stable light emission for PMT photon counting evaluation.

[0042] Combine Figure 1 、 2 As shown, as an optional embodiment, the power regulation sub-circuit 200 includes a first operational amplifier U1, a first resistor R1, a second resistor R2, an adjustable resistor VR1, a first capacitor C1 and a voltage reference chip U2.

[0043] The output end of the voltage reference chip U2 is first connected in series with the first resistor R1, and then connected to the tap end and one end of the adjustable resistor VR1. The other end of the adjustable resistor VR1 is grounded. The output end of the voltage reference chip U2 is also connected to the reference voltage V REF .

[0044] A second resistor R2 is connected in series to a node where the first resistor R1 and the adjustable resistor VR1 are connected in series, and then connected to a non-inverting input terminal of the first operational amplifier U1.

[0045] A first capacitor C1 is connected between the inverting input terminal and the output terminal of the first operational amplifier U1 .

[0046] An output end of the first operational amplifier U1 is connected to one end of the LED light emitting diode D1 , and the other end of the LED light emitting diode D1 is connected to a power supply circuit, and is powered by the power supply circuit.

[0047] It should be understood that in embodiments of the present invention, the power circuit can be designed in an appropriate manner to provide power to the LED light source. As an example, the power circuit is configured and powered by batteries, including rechargeable batteries. For example, the power circuit is composed of a battery compartment, batteries, and a switching circuit. The battery compartment can accommodate two AAA batteries and be installed in parallel. When the light source circuit is at full power output, the light source can maintain continuous output for more than 200 hours.

[0048] The switching circuit can adopt a single-pole double-throw dial switch to control the path of the current to realize the on-off of the power circuit to control the on or off state of the light source.

[0049] As an optional method, two AAA batteries are installed according to the positive and negative pole instructions in the battery box. The positive wire leading out of the battery box is connected to one end of the switch, and the negative wire is connected to the ground of the back-end circuit. The switch circuit is controlled to connect or disconnect the battery's power supply to the back-end circuit to realize the on or off state of the light source.

[0050] As an example, a switching circuit consists of an 8-pin single-pole, double-throw (SPDT) mechanical switch and an ADG721BRM multiplexer. According to the circuit design, one end of the 8-pin SPDT mechanical switch is connected to the battery compartment of the continuous power supply circuit, and the other end is connected to the ADG721BRM multiplexer. When the switch paddle is in the center, the battery compartment of the continuous power supply circuit and the ADG721BRM are physically isolated due to the open switch, and the circuit is disconnected. When the paddle is moved to the side, the battery compartment and the ADG721BRM are connected due to the closed switch, and the entire circuit is connected.

[0051] Combine Figure 2 As shown, by adjusting the resistance of the adjustable resistor VR1, the resistance of the equivalent resistor in the power regulation sub-circuit chain changes, so as to adjust the voltage value of the non-inverting input terminal of the first operational amplifier U1, thereby changing the voltage value of the inverting input terminal of the first operational amplifier U1. The change of the inverting input terminal voltage value further changes the voltage value U of the output terminal of the first operational amplifier U1 through the first capacitor C1 connected across the inverting input terminal and the output terminal. OUT , thereby adjusting the change in the output power of the LED light emitting diode D1.

[0052] Combine Figure 1 、 3 As shown, as an optional embodiment, the light emission stabilization control sub-circuit 300 includes a second operational amplifier U3, a photodiode PD1, a second capacitor C2, a third resistor R3 and a fourth resistor R4.

[0053] Photodiode PD1 is located between the inverting and non-inverting inputs of the second operational amplifier U3. Its anode is connected to the non-inverting input of the second operational amplifier U3 and to ground. Its cathode is connected to the inverting input of the second operational amplifier U3. The inverting input and output are connected via a third resistor R3, forming a negative feedback circuit.

[0054] The output terminal of the second operational amplifier U3 is connected to the inverting input terminal of the first operational amplifier U1 in the power regulation sub-circuit through the fourth resistor R4; in a dark environment, the voltage across the photodiode PD1 is forced to be 0V.

[0055] Through the light shielding treatment of the light shielding and light emitting structures, the light emitted by the LED D1 in the power regulation subcircuit hits the photodiode PD1 and generates a current from the anode to the cathode, which is manifested as an increase in the output voltage of the second operational amplifier U3.

[0056] Therefore, the flow of electrons and holes in the photodiode PD1 controlled by light on its PN junction causes current to be conducted from the cathode to the anode of the diode, wherein the current output by the photodiode PD1 increases as the brightness of the LED light emitting diode D1 increases.

[0057] Combine Figure 1 、 3 As shown, the current of the photodiode PD1 changes with the light emitted by the collected LED light-emitting diode D1, and the change is fed back to the inverting input terminal of the first operational amplifier U1 of the power regulation sub-circuit through the negative feedback circuit, so that the positive and inverting input terminal voltages of the first operational amplifier U1 remain equal, thereby achieving the function of stabilizing the luminous power of the LED light-emitting diode.

[0058] Combine Figure 1 As shown, according to the design of the LED light source circuit, the control process of the LED light source is as follows:

[0059] Adjust the resistance of the variable resistor VR1 so that the resistance of the variable resistor VR1 becomes larger, and the voltage division obtained thereby increases, further increasing the voltage Ui+ of the non-inverting input terminal of the first operational amplifier U1. Since the voltages of the positive and negative input terminals of the first operational amplifier U1 remain equal, the voltage Ui- of the negative input terminal increases, and the voltage Ui- of the output terminal of the first operational amplifier U1 increases. OUT As it increases, the output power of the LED light-emitting diode D1 increases and the light becomes stronger;

[0060] As the output power of LED D1 increases and the light becomes stronger, the photodiode PD1 receives the enhanced light, and the current ipd flowing on the PN junction increases, and the U of the second operational amplifier U3 increases. OUTThe voltage is increased and fed back to the inverting input terminal Ui- of the first operational amplifier U1, and increases until the LED D1 emits light stably and the entire circuit reaches a balanced state.

[0061] As an optional embodiment, in the design of the aforementioned LED light source circuit, the LED light emitting diode 100 adopts a KP-2012MBC light emitting diode.

[0062] As an example of the design of the power regulation sub-circuit 200, the voltage reference chip U2 adopts a precision shunt voltage reference reference chip, such as TI's LM series chips LM336MX, LM4040, and LM4041, which adopts a shunt working mode and can output a stable reference voltage with an accuracy of up to ±1%.

[0063] As an example of the design of an LED light source circuit, the first operational amplifier U1 and the second operational amplifier U3 can be low-power precision operational amplifiers, such as TLV2381, TLV2382, or SGM8240 from TI.

[0064] Among them, the adjustable resistor VR1 is a 100K-200K adjustable resistor. By adjusting the resistance of the adjustable resistor, the resistance of the equivalent resistor in the link can be changed, thereby affecting the change of current. The change of current directly affects the change of the output power of the LED light-emitting diode, realizing the function of adjusting the power of the light source.

[0065] As an example, the photodiode PD1 adopts a semiconductor photosensitive diode based on a PN junction, detects light signals based on the photocurrent characteristics and realizes photoelectric conversion output. The photodiode PD1 of this embodiment adopts a photosensitive diode with an operating range in the visible light band, such as the silicon PIN photosensitive diode of Hamamatsu, Japan.

[0066] In order to make the photodiode PD1 and the light emitting diode D1 work in an ideal manner, the light-shielding and light-emitting structure is very important. Figure 4A 、 4B As shown, the light-shielding and light-emitting structures proposed in the present invention are used to achieve the functions of fixing, light-shielding and light-emitting.

[0067] Combine Figure 4A 、 4B As shown, the light-shielding and light-emitting structure 400 has grooves 401 of corresponding heights dug out according to the heights of the photodiode PD1 and the LED light-emitting diode D1, so as to seamlessly fit onto the PCB circuit board without being interfered with by the heights of the photodiode PD1 and the LED light-emitting diode D1, thereby achieving a light-shielding effect.

[0068] As shown in the figure, the overall light-shielding and light-emitting structure is designed as a "mountain"-shaped structure according to the layout of circuit board components and the shell of the light source. Based on this, one side surface of the light-shielding groove is set as a flat surface, which is seamlessly bonded to the PCB circuit board and adhered to the PCB circuit board through an adhesive layer, such as Kraft glue, to achieve the functions of light-shielding, light-emitting and fixing.

[0069] As an optional embodiment, the light exit hole 402 is a through micro-hole with a diameter of 1 Å.

[0070] Furthermore, the flat surface is provided with at least two fixing holes 403 with a diameter of 2 mm to achieve the fixing function, which is tightened and fixed by screws.

[0071] As an optional embodiment, the diffuser is a transparent, uniformly diffuser lens used to widen the light-emitting surface of the light source and evenly diffuse the light. It is disposed within the circular groove 404 on the other side of the flat surface. As an example, the uniformly diffuser lens is made of a lightweight, hard, and transparent acrylic material to evenly diffuse the light emitted by the LED through the light shielding and light emitting structures, thereby facilitating the PMT module lens to receive the light source.

[0072] {Example 2}

[0073] The sensitivity of the PMT photon counting module was tested using the LED light source proposed in the present invention in conjunction with the photon counting software. The test results are as follows: Figure 5 As shown. The test results show that the light power emitted by the LED light source designed by the present invention is very stable. After 30 minutes of testing, the sensitivity CV value obtained is 0.1%. The LED light source designed by the present invention can achieve an ultra-long single working time of the LED light source, reaching more than 200 hours. Combined with the light-shielding and light-emitting structures, the photodiode is shielded from light sources other than the LED so that it can adjust the circuit current in time to ultimately achieve accurate, continuous and stable LED light power. It provides a high-precision, continuous and stable standard light source for effectively testing the sensitivity of the PMT photon counting module, ensuring the efficient completion and test accuracy of the photon counter counting sensitivity test.

[0074] While the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Persons skilled in the art will readily appreciate that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. An LED light source capable of outputting stable power for PMT photon counting evaluation, characterized in that: Including LED light source circuit, light-proof and light-emitting structure; The LED light source circuit includes an LED light emitting diode, a power regulation subcircuit and a light emitting stabilization regulation subcircuit; The LED light emitting diode is arranged at the output end of the power regulating subcircuit, and the output power of the LED light emitting diode is controlled and regulated by the power regulating subcircuit; The light emitting stabilization regulating subcircuit is connected to the power regulating subcircuit and is used to feed back the changes in the luminous intensity of the LED light emitting diode collected in real time to the power regulating subcircuit via a negative feedback circuit, so that the output of the power regulating subcircuit remains stable, thereby regulating the stable luminous power of the LED light source circuit; The light-shielding and light-emitting structures are both arranged on the LED light source PCB circuit board, and the light-shielding and light-emitting structures are set at the position of the LED light source circuit corresponding to the LED light-emitting diode; wherein, a light-shielding groove is set on one side surface of the light-shielding and light-emitting structure, and the LED light-emitting diode is accommodated in the light-shielding groove, and a through microhole is opened in the light-shielding groove at a position directly in front of the LED light-emitting diode as a light-emitting hole; a circular groove is set on the other side surface of the light-shielding and light-emitting structure, and the circular groove takes the light-emitting hole as the center of the circle; a diffuser with a shape and depth adapted to the circular groove is arranged in the circular groove, which is used to evenly diffuse the light output through the light-emitting hole and widen the luminous surface of the light source.

2. The LED light source capable of outputting stable power for PMT photon counting evaluation according to claim 1, characterized in that: The power regulation subcircuit includes a first operational amplifier U1, a first resistor R1, a second resistor R2, an adjustable resistor VR1, a first capacitor C1 and a voltage reference chip U2; The output end of the voltage reference chip U2 is first connected in series with the first resistor R1, and then connected to the tap end and one end of the adjustable resistor VR1, and the other end of the adjustable resistor VR1 is grounded; the output end of the voltage reference chip U2 is also connected to the reference voltage V REF ; A second resistor R2 is connected in series to the node where the first resistor R1 and the adjustable resistor VR1 are connected in series, and then connected to the non-inverting input terminal of the first operational amplifier U1; A first capacitor C1 is connected between the inverting input terminal and the output terminal of the first operational amplifier U1; The output end of the first operational amplifier U1 is connected to one end of the LED light emitting diode D1 , and the other end of the LED light emitting diode D1 is connected to a power supply circuit, and is powered by the power supply circuit.

3. The LED light source capable of outputting stable power for PMT photon counting evaluation according to claim 2, characterized in that: By adjusting the resistance of the adjustable resistor VR1, the resistance of the equivalent resistor in the power regulation sub-circuit chain changes, thereby adjusting the voltage value of the non-inverting input terminal of the first operational amplifier U1, thereby changing the voltage value of the inverting input terminal of the first operational amplifier U1. The change in the voltage value of the inverting input terminal further changes the voltage value U of the output terminal of the first operational amplifier U1 through the first capacitor C1 connected across the inverting input terminal and the output terminal. OUT , thereby adjusting the change in the output power of the LED light emitting diode.

4. The LED light source capable of outputting stable power for PMT photon counting evaluation according to claim 2, characterized in that: The light emitting stabilization control sub-circuit includes a second operational amplifier U3, a photodiode PD1, a second capacitor C2, a third resistor R3 and a fourth resistor R4; The photodiode PD1 is located at the inverting and non-inverting input terminals of the second operational amplifier U3; the positive electrode of the photodiode PD1 is connected to the non-inverting input terminal of the second operational amplifier U3 and is grounded, the negative electrode of the photodiode PD1 is connected to the inverting input terminal of the second operational amplifier U3, and the inverting input terminal and the output terminal are connected via a third resistor R3 to form a negative feedback circuit; The output terminal of the second operational amplifier U3 is connected to the inverting input terminal of the first operational amplifier U1 in the power regulation sub-circuit through the fourth resistor R4; in a dark environment, the voltage across the photodiode PD1 is forced to be 0V; Through the light-shielding treatment of the light-shielding and light-emitting structures, the light emitted by the LED D1 in the power regulation subcircuit hits the photodiode PD1, generating a current from the anode to the cathode, which is manifested as an increase in the output voltage of the second operational amplifier U3; The flow of electrons and holes in the photodiode PD1 controlled by light on its PN junction causes current to be conducted from the cathode to the anode of the diode, wherein the current output by the photodiode PD1 increases as the brightness of the LED light emitting diode D1 increases.

5. The LED light source capable of outputting stable power for PMT photon counting evaluation according to claim 4, characterized in that: The current of the photodiode PD1 changes with the light emitted by the collected LED light-emitting diode D1, and the change is fed back to the inverting input terminal of the first operational amplifier U1 of the power regulation sub-circuit through a negative feedback circuit, so that the positive and inverting input terminal voltages of the first operational amplifier U1 remain equal, thereby achieving the function of stabilizing the luminous power of the LED light-emitting diode.

6. The LED light source capable of outputting stable power for PMT photon counting evaluation according to claim 4, characterized in that: The light-shielding and light-emitting structures are respectively dug out with grooves of corresponding heights according to the heights of the photodiode PD1 and the LED light-emitting diode D1, so as to seamlessly fit onto the PCB circuit board without being interfered with by the heights of the photodiode PD1 and the LED light-emitting diode D1, thereby achieving a light-shielding effect.

7. The LED light source capable of outputting stable power for PMT photon counting evaluation according to claim 6, characterized in that: On the light-shielding and light-emitting structure, one side surface of the light-shielding groove is provided as a flat surface, which is seamlessly attached to the PCB circuit board and is adhered to the PCB circuit board through an adhesive layer.

8. The LED light source capable of outputting stable power for PMT photon counting evaluation according to claim 1, characterized in that: The light-emitting hole is a through microhole with a diameter of 1 mm.

9. The LED light source capable of outputting stable power for PMT photon counting evaluation according to claim 1, characterized in that: The diffusing sheet is a uniform diffusing lens made of transparent material.

10. A method for controlling an LED light source capable of outputting stable power for PMT photon counting evaluation according to any one of claims 1 to 9, characterized in that: The following steps are involved: Adjust the resistance of the adjustable resistor VR1 so that the resistance of the adjustable resistor VR1 becomes larger, and the voltage division obtained thereby increases, further increasing the voltage Ui+ of the non-inverting input terminal of the first operational amplifier U1. Since the voltages of the positive and negative input terminals of the first operational amplifier U1 remain equal, the voltage Ui- of the negative input terminal increases, and the voltage Ui- of the output terminal of the first operational amplifier U1 increases. OUT As it increases, the output power of the LED light-emitting diode D1 increases and the light becomes stronger; As the output power of LED D1 increases and the light becomes stronger, the photodiode PD1 receives the enhanced light, and the current ipd flowing on the PN junction increases, and the U of the second operational amplifier U3 increases. OUT The voltage is increased and fed back to the inverting input terminal Ui- of the first operational amplifier U1, and increases until the LED D1 emits light stably and the entire circuit reaches a balanced state.

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