Background suppression photoelectric circuit and photoelectric sensor

Abstract

The utility model provides a background suppression photoelectric circuit and a photoelectric sensor. The circuit comprises a control unit, a light receiving tube, an operational amplification unit, a transmitting tube, a driving unit and an NPN output unit. The transmitting tube and the driving unit transmit optical signals to an object to be measured, the light receiving tube and the operational amplification unit receive the reflected optical signals, convert the reflected optical signals into current or voltage signals and output amplified signals, and the control unit receives the amplified signals, processes the amplified signals and outputs control signals. The NPN output unit receives and processes the control signal and then outputs a switching value signal. Through the light signals emitted by the transmitting tube and the driving unit, and the reflected light signals are received by the light receiving tube and the operational amplification unit, the circuit can effectively detect an object to be measured, and the sensitivity in a complex and changeable environment is maintained.

Description

Technical Field

[0001] The utility model relates to the field of optoelectronic sensors, in particular to a background suppression optoelectronic circuit and an optoelectronic sensor. Background Art

[0002] Optoelectronic sensors are widely used in the fields of industrial automation, safety monitoring, etc. However, existing optoelectronic sensors often have deviations when detecting objects of different colors, especially the detection effect for black and dark objects is not good. This limitation leads to a decrease in detection accuracy in complex backgrounds, affecting the actual application range of the sensors.

[0003] In addition, the detection distance of traditional optoelectronic sensors is usually fixed and it is difficult to flexibly adjust according to the requirements of different application scenarios. This inflexibility limits the applicability of the sensors in diverse environments and increases the cost of equipment selection and replacement.

[0004] There are also deficiencies in the signal processing of optoelectronic sensors in the prior art. Due to the lack of effective signal amplification and processing mechanisms, the performance of sensors in the case of long-distance detection or weak reflection signals is often unsatisfactory, which directly affects the reliability and stability of detection.

[0005] Another prominent problem is background interference. In a complex industrial environment, the color and reflection characteristics of background objects may have a significant impact on the detection results, resulting in false detections or missed detections. This background dependence severely limits the application effect of optoelectronic sensors in changing environments. Therefore, a new type of optoelectronic sensor is needed. Summary of the Utility Model

[0006] The purpose of the utility model is to provide a background suppression optoelectronic sensor with high stability.

[0007] In the first aspect, the utility model provides a background suppression optoelectronic circuit, which includes a control unit, a light receiving tube and an operational amplification unit, a light emitting tube and a driving unit, and an NPN output unit;

[0008] The light emitting tube and the driving unit emit a light signal to the object to be measured, the light receiving tube and the operational amplification unit receive the reflected light signal and convert it into a current or voltage signal and output an amplified signal, the control unit receives the amplified signal, processes it and outputs a control signal, and the NPN output unit receives the control signal, processes it and outputs a switching quantity signal.

[0009] Further, the transmitting tube and the driving unit include a first resistor. One end of the first resistor is connected to the power supply terminal, and the other end is respectively connected to the positive electrode of the first polarized capacitor and the positive electrode of the first light-emitting diode. The negative electrode of the first polarized capacitor is grounded, and the negative electrode of the first light-emitting diode is connected to the collector of the first triode.

[0010] The emitter of the first triode is grounded after being connected in series with a second resistor. The base is respectively connected to one end of a third resistor and a fourth resistor. The other end of the third resistor is connected to the control unit, and the other end of the fourth resistor is grounded.

[0011] Further, the control unit includes a control chip. The fifth pin of the control chip is connected to the power supply terminal, the seventh pin is grounded, and the twenty-first pin is grounded.

[0012] Further, the light-receiving tube and the operational amplification unit include a first amplifier and a second amplifier.

[0013] The first pin of the first amplifier is respectively connected to a fifth resistor and a first capacitor. The fifth resistor is connected in series with a sixth resistor and a second capacitor and then respectively connected to the negative electrode of the second light-emitting diode and one end of a seventh resistor. The other end of the seventh resistor is connected to the ground after being connected in series with a first diode. An eighth resistor is connected in parallel across the two ends after the second capacitor and the seventh resistor are connected in series. A ninth resistor is connected to the positive electrode of the first diode and then connected to the power supply terminal. A third capacitor is connected in parallel with the first diode.

[0014] The second pin of the first amplifier is connected between the fifth resistor and the sixth resistor. The third pin of the first amplifier is respectively connected to one end of a tenth resistor and an eleventh resistor. A twelfth resistor is connected in parallel across the two ends after the tenth resistor and the eleventh resistor are connected in series. The other end of the tenth resistor is connected to the positive electrode of the second diode and one end of a thirteenth resistor after being connected in series with a fourth capacitor. The other end of the thirteenth resistor is connected to the positive electrode of the first diode. The other end of the eleventh resistor is connected to the positive electrode of the first diode. The fifth pin of the first amplifier is respectively connected to the negative electrodes of the second light-emitting diode and the third light-emitting diode and then connected to the power supply terminal.

[0015] The first pin of the second amplifier is respectively connected to the control unit and a fourteenth resistor. The fourteenth resistor is respectively connected to the first pin of the second amplifier and one end of a fifteenth resistor. The other end of the fifteenth resistor is connected to the positive electrode of the first diode. The third pin of the second amplifier is respectively connected to one end of a sixteenth resistor and the first capacitor. The other end of the sixteenth resistor is connected to the positive electrode of the first diode.

[0016] Further, the NPN output unit includes a first input terminal and a second input terminal, and the first input terminal and the second input terminal are respectively connected to the control unit.

[0017] Further, one end of the seventeenth resistor is connected in series to the first input terminal and is respectively connected to one end of the eighteenth resistor and the base of the second triode, and the other end of the eighteenth resistor is grounded;

[0018] The collector of the second triode is respectively connected to the first output terminal, the negative electrode of the second diode and one end of the nineteenth resistor. The positive electrode of the second diode is grounded, and the other end of the nineteenth resistor is connected to the second output terminal after being connected in series with the twentieth resistor; the emitter of the second triode is respectively connected to one end of the twenty-first resistor and the twenty-second resistor. The other end of the twenty-first resistor is connected to the control unit, and the other end of the twenty-second resistor is grounded;

[0019] One end of the twenty-third resistor is connected in series to the second input terminal and is connected to the base of the third triode. The collector of the third triode is connected to the second output terminal. The emitter of the third triode is respectively connected to one end of the twenty-fourth resistor and the twenty-fifth resistor. The other end of the twenty-fourth resistor is connected to the control unit, and the other end of the twenty-fifth resistor is grounded.

[0020] Further, it further includes a power supply unit and a display unit. The power supply unit is respectively connected to the power supply terminals of the control unit, the emitting tube and the driving unit, the light receiving tube and the operational amplifier unit, and the display unit; the input terminal of the display unit is further connected to the control unit.

[0021] Further, the power supply unit includes a power supply chip. The first pin of the power supply chip is respectively connected in series with a fifth capacitor and a sixth capacitor and then grounded, and the first pin of the power supply chip is further connected to the power supply terminal;

[0022] The second pin of the power supply chip is grounded;

[0023] The third pin of the power supply chip is respectively connected to a seventh capacitor, an eighth capacitor and the negative electrode of a third diode and is grounded; the third pin is further connected to a twenty-sixth resistor, and the twenty-sixth resistor is connected to the power supply terminal after being connected in series with a fourth diode.

[0024] Further, the display unit includes a fourth light-emitting diode and a fifth light-emitting diode, and the positive electrode of the fourth light-emitting diode is connected to the positive electrode of the fifth light-emitting diode;

[0025] The negative electrode of the fourth light-emitting diode is connected to the control unit after being serially connected with a twenty-seventh resistor, and the negative electrode of the fifth light-emitting diode is connected to the control unit after being serially connected with a twenty-eighth resistor; a power supply terminal is also connected between the positive electrodes of the fourth light-emitting diode and the fifth light-emitting diode.

[0026] In a second aspect, the present utility model further provides an optoelectronic device, which adopts the background suppression optoelectronic circuit described in any one of the above.

[0027] Compared with the prior art, the present utility model at least includes the following beneficial effects: By emitting an optical signal through the transmitting tube and the driving unit, and using the light-receiving tube and the operational amplifier unit to receive the reflected optical signal, the circuit can effectively detect the object to be measured and maintain the sensitivity in a complex and changeable environment. The operational amplifier unit amplifies and processes the reflected optical signal, improving the signal-to-noise ratio of the signal, enabling the control unit to process the signal more accurately. The NPN output unit converts the control signal into a digital signal, facilitating integration and interaction with other electronic systems or devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0029] Figure 1 It is a block diagram of the background suppression optoelectronic circuit in an embodiment of the present utility model;

[0030] Figure 2 It is a circuit schematic diagram of the transmitting tube and the driving unit in an embodiment of the present utility model;

[0031] Figure 3 It is a circuit schematic diagram of the control unit in an embodiment of the present utility model;

[0032] Figure 4 It is a circuit schematic diagram of the light-receiving tube and the operational amplifier unit in an embodiment of the present utility model;

[0033] Figure 5 It is a circuit schematic diagram of the NPN output unit in an embodiment of the present utility model;

[0034] Figure 6 It is a circuit schematic diagram of the power supply unit in an embodiment of the present utility model;

[0035] Figure 7 It is a circuit schematic diagram of the display unit in an embodiment of the present utility model;

[0036] Figure 8 This is a module diagram of the background suppression optoelectronic circuit in another embodiment of the present utility model.

[0037] Among them, R1 - the first resistor; R2 - the second resistor; R3 - the third resistor; R4 - the fourth resistor; R5 - the fifth resistor; R6 - the sixth resistor; R7 - the seventh resistor; R8 - the eighth resistor; R9 - the ninth resistor; R10 - the tenth resistor; R11 - the eleventh resistor; R12 - the twelfth resistor; R13 - the thirteenth resistor; R14 - the fourteenth resistor; R15 - the fifteenth resistor; R16 - the sixteenth resistor; R17 - the seventeenth resistor; R18 - the eighteenth resistor; R19 - the nineteenth resistor; R20 - the twentieth resistor; R21 - the twenty - first resistor; R22 - the twenty - second resistor; R23 - the twenty - third resistor; R24 - the twenty - fourth resistor; R25 - the twenty - fifth resistor; R26 - the twenty - sixth resistor; R27 - the twenty - seventh resistor; R28 - the twenty - eighth resistor; C11 - the first polarized capacitor; C1 - the first capacitor; C2 - the second capacitor; C3 - the third capacitor; C4 - the fourth capacitor; C5 - the fifth capacitor; C6 - the sixth capacitor; C7 - the seventh capacitor; C8 - the eighth capacitor; D1 - the first diode; D2 - the second diode; D3 - the third diode; D4 - the fourth diode; U1 - the first light - emitting diode; U2 - the second light - emitting diode; U3 - the third light - emitting diode; U4 - the fourth light - emitting diode; Q1 - the first triode; Q2 - the second triode; Q3 - the third triode. Detailed implementation manners

[0038] The following will describe a background suppression optoelectronic circuit and an optoelectronic sensor of the present utility model in more detail with reference to the schematic diagrams, which show the preferred embodiments of the present utility model. It should be understood that those skilled in the art can modify the present utility model described herein while still achieving the advantageous effects of the present utility model. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation on the present utility model.

[0039] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non - exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0040] The present utility model will be described more specifically by way of example with reference to the accompanying drawings in the following paragraphs. According to the following description, the advantages and features of the present utility model will be clearer. It should be noted that the attached drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the embodiments of the present utility model.

[0041] In a first aspect, the present utility model provides a background suppression optoelectronic circuit, as Figure 1 shown, which includes a control unit, a light receiving tube and an operational amplifier unit, a transmitting tube and a driving unit, and an NPN output unit;

[0042] The transmitting tube and the driving unit emit a light signal onto the object to be measured. The light receiving tube and the operational amplifier unit receive the reflected light signal, convert it into a current or voltage signal, and output an amplified signal. The control unit receives the amplified signal, processes it, and outputs a control signal. The NPN output unit receives the control signal, processes it, and outputs a digital quantity signal.

[0043] Specifically, the present utility model irradiates the object with the light emitted by the transmitting tube, and the signal is reflected back from the object to the signal acquisition and receiving tube. Subsequently, these reflected light signals are amplified and processed by the operational amplifier and its supporting circuit, and finally input into the internal processing system of the single-chip microcomputer, so as to realize the accurate detection of the distance of the object. In addition, the signal acquisition part adopts a special design, significantly improving the reflectivity of black and dark objects, effectively increasing the detection distance of the sensor for these low-reflectivity objects. At the same time, the sensor has excellent adaptability to backgrounds of different colors, ensuring that there will be no offset error during the detection process, and guaranteeing the accuracy and reliability of the detection.

[0044] Furthermore, as Figure 2 shown, the transmitting tube and the driving unit include a first resistor R1. One end of the first resistor R1 is connected to the power supply terminal, and the other end is respectively connected to the positive electrode of the first polarized capacitor C11 and the positive electrode of the first light-emitting diode U1. The negative electrode of the first polarized capacitor C11 is grounded, and the negative electrode of the first light-emitting diode U1 is connected to the collector of the first triode Q1;

[0045] The emitter of the first triode Q1 is grounded in series with a second resistor R2, and the base is respectively connected in series with one end of a third resistor R3 and a fourth resistor R4. The other end of the third resistor R3 is connected to the control unit, and the other end of the fourth resistor R4 is grounded.

[0046] Specifically, this part is completed by a dedicated emitting diode and a driving circuit. While emitting light with a stable frequency, after shaping the voltage ripple and filtering out the clutter through a tantalum capacitor, the operating noise frequency of the transmitting tube is reduced to a range outside the audible range of the human ear, realizing the function of eliminating noise.

[0047] In a possible embodiment of the present utility model, the first polar capacitor C11 filters to provide a stable current for the first light-emitting diode U1 (i.e., the emitting tube). The first triode Q1 acts as a switch or an amplifier, and its base voltage is determined by the voltage division of the third resistor R3 and the fourth resistor R4. The control unit adjusts the conduction degree of the first triode Q1 by changing the voltage on the third resistor R3, thereby controlling the brightness of the emitting tube. The second resistor R2 ensures that the first triode Q1 can work stably during emission and will not be damaged due to excessive current. The third resistor R3 is connected to the control unit, allowing an external signal to control the intensity of the emitted light, which is used to adjust the detection distance or respond to different environmental conditions.

[0048] Further, as Figure 3 shown, the control unit includes a control chip; the fifth pin of the control chip is connected to the power supply terminal, the seventh pin is grounded, and the twenty-first pin is grounded.

[0049] In a possible embodiment of the present utility model, the control chip uses a single-chip microcomputer of the STC8G series, which has characteristics such as strong anti-interference, ultra-low price, high speed, and low power consumption. At the same working frequency, the STC8G series single-chip microcomputer is about 12 times faster than the traditional 8051. To sequentially execute all 111 instructions, the STC8G series single-chip microcomputer only requires 147 clocks. There are 3 optional clock sources inside the single-chip microcomputer, providing two low-power modes, and having rich digital peripherals (serial port, timer, PCA, PWM, as well as I2C, SPI) interfaces and analog peripherals (ultra-high-speed ADC, comparator), which can meet most design requirements.

[0050] In this embodiment, the fifth pin of the control chip is connected to the power supply terminal to ensure that the chip obtains a stable power supply to execute its functions. The seventh pin and the twenty-first pin are grounded, providing a reference point for the circuit, which helps to stabilize the working state of the circuit and reduce interference. The control chip receives signals from the sensor, processes them, and then adjusts the intensity or mode of the emitted light by controlling the emitting tube and the driving unit.

[0051] Further, as Figure 4 shown, the light-receiving tube and the operational amplification unit include a first amplifier and a second amplifier;

[0052] The first pin of the first amplifier is respectively connected to a fifth resistor R5 and a first capacitor C1. The fifth resistor R5 is connected in series with a sixth resistor R6 and a second capacitor C2 and then respectively connected to the negative electrode of a second light-emitting diode U2 and one end of a seventh resistor R7. The other end of the seventh resistor R7 is connected to the ground after being connected in series with a first diode D1; an eighth resistor R8 is connected in parallel across the two ends after the second capacitor C2 and the seventh resistor R7 are connected in series; a ninth resistor R9 is connected to the positive electrode of the first diode D1 and then connected to the power supply terminal; a third capacitor C3 is connected in parallel with the first diode D1;

[0053] The second pin of the first amplifier is connected between the fifth resistor R5 and the sixth resistor R6; the third pin of the first amplifier is respectively connected to one end of a tenth resistor R10 and an eleventh resistor R11. A twelfth resistor R12 is connected in parallel across the two ends after the tenth resistor R10 and the eleventh resistor R11 are connected in series; the other end of the tenth resistor R10 is connected in series with a fourth capacitor C4 and then respectively connected to the positive electrode of a second diode D2 and one end of a thirteenth resistor R13. The other end of the thirteenth resistor R13 is connected to the positive electrode of the first diode D1; the other end of the eleventh resistor R11 is connected to the positive electrode of the first diode D1; the fifth pin of the first amplifier is respectively connected to the negative electrodes of the second light-emitting diode U2 and the third light-emitting diode U3 and then connected to the power supply terminal;

[0054] The first pin of the second amplifier is respectively connected to the control unit and a fourteenth resistor R14. The fourteenth resistor R14 is respectively connected to the first pin of the second amplifier and one end of a fifteenth resistor R15. The other end of the fifteenth resistor R15 is connected to the positive electrode of the first diode D1; the third pin of the second amplifier is respectively connected to one end of a sixteenth resistor R16 and the first capacitor C1. The other end of the sixteenth resistor R16 is connected to the positive electrode of the first diode D1.

[0055] Specifically, in a possible embodiment of the present invention, the first pin of the first amplifier receives a signal from a light-receiving tube, and this signal is filtered by the fifth resistor R5 and the first capacitor C1. The first amplifier amplifies the input signal and outputs it through its third pin. The connection of the second pin is used to achieve feedback to stabilize the gain or bias of the amplifier. The connection of the fifth pin provides a working voltage for the amplifier and a reference voltage for other circuit elements. The first diode D1 and the ninth resistor R9 are used to protect the amplifier from reverse voltage damage. The first pin of the second amplifier is connected to the control unit for receiving a control signal or providing feedback.

[0056] In another possible embodiment of the present utility model, the light receiving tube and the operational amplifier unit are completed by using a dedicated signal receiving diode and then through an operational amplifier circuit. The light emitted by the transmitting tube contacts an object and then is reflected onto the PD of the signal acquisition and receiving tube. The first stage of the operational amplifier amplifies and filters the signal collected by the receiving tube and then conveys it to the second stage. After further amplification and filtering, it is output to the ADC sampling pin of the single-chip microcomputer to achieve the specific functions required. The light receiving tube and the operational amplifier unit select a dual-channel operational amplifier, which can work at a lower power supply voltage, has a lower static current, and the common-mode input range includes negative power supply, thus eliminating the need for external bias components in many applications. This chip has short-circuit protection output, a true differential input stage, low input bias current, internal compensation, common-mode range extended to negative power supply, single and split supply operation, and an anti-static clamp is installed at the input terminal to increase the robustness of the device without affecting its operation and other characteristics.

[0057] Further, as Figure 5 shown, the NPN output unit includes a first input terminal and a second input terminal, and the first input terminal and the second input terminal are respectively connected to the control unit.

[0058] Further, the first input terminal is connected to one end of the eighteenth resistor R18 and the base of the second triode Q2 after being serially connected with the seventeenth resistor R17, and the other end of the eighteenth resistor R18 is grounded;

[0059] The collector of the second triode Q2 is respectively connected to the first output terminal, the negative electrode of the second diode D2 and one end of the nineteenth resistor R19. The positive electrode of the second diode D2 is grounded, and the other end of the nineteenth resistor R19 is connected to the second output terminal after being serially connected with the twentieth resistor R20; the emitter of the second triode Q2 is respectively connected to one end of the twenty-first resistor R21 and the twenty-second resistor R22. The other end of the twenty-first resistor R21 is connected to the control unit, and the other end of the twenty-second resistor R22 is grounded;

[0060] The second input terminal is connected to the base of the third triode Q3 after being serially connected with the twenty-third resistor R23. The collector of the third triode Q3 is connected to the second output terminal. The emitter of the third triode Q3 is respectively connected to one end of the twenty-fourth resistor R24 and the twenty-fifth resistor R25. The other end of the twenty-fourth resistor R24 is connected to the control unit, and the other end of the twenty-fifth resistor R25 is grounded.

[0061] Specifically, the second triode Q2 and the third triode Q3 serve as switching or amplifying elements, and are turned on or off according to the signals of the control unit, thereby controlling the voltage state of the output terminal. The seventeenth resistor R17 and the eighteenth resistor R18 provide an appropriate bias voltage for the second triode Q2. The second diode D2 is used to protect the second triode Q2 from reverse voltage. The nineteenth resistor R19, the twentieth resistor R20, the twenty-first resistor R21, the twenty-second resistor R22, the twenty-fourth resistor R24, and the twenty-fifth resistor R25 are used to limit current and distribute voltage to ensure the stable operation of the circuit.

[0062] In a possible embodiment of the present invention, the NPN output unit adopts a two-wire switch output mode, and the microcontroller uses the push-pull output GPIO port to drive the backend NPN output circuit. When the measured object is within the interval or not within the interval, according to the two different states, the GPIO states of the two ports of output A and output B are changed simultaneously, and the two states are guaranteed to be mutually exclusive. When P3.4 outputs a high level, Q2 is turned on, and the output terminal OUT_A changes from the original high level to a low level. When P3.4 outputs a high level, P3.2 outputs a low level according to the mutual exclusion principle, Q4 is turned off, and the output terminal OUT_B is in a high level state. Conversely, repeat the above process.

[0063] Further, as Figure 6 , Figure 7 and Figure 8 shown, it further includes a power supply unit and a display unit. The power supply unit is respectively connected to the power supply terminals of the control unit, the transmitting tube and the driving unit, the light receiving tube and the operational amplifier unit, and the display unit; the input terminal of the display unit is also connected to the control unit.

[0064] Further, the power supply unit includes a power supply chip. The first pin of the power supply chip is grounded after being serially connected with a fifth capacitor C5 and a sixth capacitor C6 respectively, and the first pin of the power supply chip is also connected to the power supply terminal;

[0065] The second pin of the power supply chip is grounded;

[0066] The third pin of the power supply chip is respectively connected to a seventh capacitor C7, an eighth capacitor C8, and the negative electrode of a third diode D3 and grounded; the third pin is also connected to a twenty-sixth resistor R26, and the twenty-sixth resistor R26 is serially connected with a fourth diode D4 and then connected to the power supply terminal.

[0067] Specifically, the design of the power supply unit ensures a stable and clean power supply for the entire system, which is crucial for the reliable operation of sensors and other electronic components. Through the configuration of diodes, the power supply unit can protect the system from power anomalies such as overvoltage or reverse polarity. The display unit provides an interface for users to interact with the system, and can display important operating information for easy user monitoring and operation.

[0068] In a possible embodiment of the present utility model, a linear voltage stabilizing chip with the model number AP7381-50Y-13 is adopted in this part of the power supply unit, which has functions such as a wide input voltage range, high precision, low voltage drop, current limiting, and ultra-low quiescent current. The chip is composed of a voltage reference, an error amplifier, and resistors. Through this chip and its peripheral circuits, the external power supply voltage is converted into the voltage value required by other components in the circuit. It effectively reduces the problem of severe heating of the sensor after long-term operation, and solves the problem of decreased sensor accuracy caused by heating after long-term operation.

[0069] Furthermore, the display unit includes a fourth light-emitting diode U4 and a fifth light-emitting diode, and the positive electrode of the fourth light-emitting diode U4 is connected to the positive electrode of the fifth light-emitting diode;

[0070] The negative electrode of the fourth light-emitting diode U4 is connected to the control unit after being serially connected with a twenty-seventh resistor R27, and the negative electrode of the fifth light-emitting diode is connected to the control unit after being serially connected with a twenty-eighth resistor R28; A power supply terminal is also connected between the positive electrodes of the fourth light-emitting diode U4 and the fifth light-emitting diode.

[0071] In an embodiment of the present utility model, the fourth light-emitting diode U4 and the fifth light-emitting diode can be used as indicator lights to display different states of the system, such as power status, sensor activation status, warning or error messages, etc. Since the diodes are connected to the control unit, the control unit can be programmed to change its lighting mode according to different inputs or system conditions to provide intuitive feedback.

[0072] In this embodiment, the fourth light-emitting diode U4 and the fifth light-emitting diode form a two-color LED lamp. Compared with a circuit using two LED lamps, the single-chip microcomputer can quickly drive the circuit to switch the indicator light color, minimizing the time required for indicator light switching as much as possible, and ensuring the voltage stability of the output signal.

[0073] In a second aspect, the present utility model also provides an optoelectronic sensor, as Figure 8 shown, adopting the background suppression optoelectronic circuit described in any one of the above. An adjustment device is further included in the optoelectronic sensor, and the adjustment device is used to adjust the position of the lens so as to adjust the detection distance.

[0074] The above uses specific examples to elaborate on the present utility model, which is only used to help understand the present utility model and is not intended to limit the present utility model. For those skilled in the technical field to which the present utility model pertains, based on the idea of the present utility model, several simple deductions, deformations or substitutions can also be made.

Claims

1. A background suppression photoelectric circuit, characterized in that: It includes a control unit, a light receiving tube and an operational amplifier unit, a transmitting tube and a driving unit, and an NPN output unit; The transmitting tube and the driving unit emit a light signal to the object to be measured, the light receiving tube and the operational amplifier unit receive the reflected light signal and convert it into a current or voltage signal and output an amplified signal, the control unit receives the amplified signal, processes it and outputs a control signal, and the NPN output unit receives the control signal and processes it and outputs a switching signal.

2. The background suppression photoelectric circuit according to claim 1, characterized in that: The transmitting tube and driving unit include a first resistor, one end of the first resistor is connected to the power supply end, and the other end is respectively connected to the positive electrode of the first polarity capacitor and the positive electrode of the first light-emitting diode; the negative electrode of the first polarity capacitor is grounded, and the negative electrode of the first light-emitting diode is connected to the collector of the first transistor; The emitter of the first transistor is connected in series with the second resistor and then grounded, the base is connected in series with one end of the third resistor and the fourth resistor respectively, the other end of the third resistor is connected to the control unit, and the other end of the fourth resistor is grounded.

3. The background suppression photoelectric circuit according to claim 1, characterized in that: The control unit comprises a control chip; the fifth pin of the control chip is connected to the power supply terminal, the seventh pin is grounded, and the twenty-first pin is grounded.

4. The background suppression photoelectric circuit according to claim 1, characterized in that: The light receiving tube and the operational amplifier unit include a first amplifier and a second amplifier; The first pin of the first amplifier is respectively connected to the fifth resistor and the first capacitor, the fifth resistor is connected in series with the sixth resistor and the second capacitor, and then connected to the cathode of the second light-emitting diode and one end of the seventh resistor, respectively, the other end of the seventh resistor is connected in series with the first diode and then grounded; the eighth resistor is connected in parallel to the two ends of the second capacitor and the seventh resistor in series; the ninth resistor is connected to the anode of the first diode and then connected to the power supply end; the third capacitor is connected in parallel with the first diode; The second pin of the first amplifier is connected between the fifth resistor and the sixth resistor; the third pin of the first amplifier is respectively connected to one end of the tenth resistor and the eleventh resistor, and the twelfth resistor is connected in parallel to both ends of the tenth resistor and the eleventh resistor in series; the other end of the tenth resistor is connected in series with the fourth capacitor and then connected to the positive electrode of the second diode and one end of the thirteenth resistor, and the other end of the thirteenth resistor is connected to the positive electrode of the first diode; the other end of the eleventh resistor is connected to the positive electrode of the first diode; the fifth pin of the first amplifier is respectively connected to the negative electrodes of the second light-emitting diode and the third light-emitting diode and then connected to the power supply terminal; The first pin of the second amplifier is respectively connected to the control unit and the fourteenth resistor, the fourteenth resistor is respectively connected to the first pin of the second amplifier and one end of the fifteenth resistor, and the other end of the fifteenth resistor is connected to the anode of the first diode; the third pin of the second amplifier is respectively connected to one end of the sixteenth resistor and the first capacitor, and the other end of the sixteenth resistor is connected to the anode of the first diode.

5. The background suppression photoelectric circuit according to claim 1, characterized in that: The NPN output unit includes a first input terminal and a second input terminal, and the first input terminal and the second input terminal are respectively connected to the control unit.

6. The background suppression photoelectric circuit according to claim 5, characterized in that: The first input terminal is connected in series with a seventeenth resistor and then connected to one end of an eighteenth resistor and the base of the second transistor, and the other end of the eighteenth resistor is grounded; The collector of the second triode is respectively connected to the first output terminal, the cathode of the second diode and one end of the nineteenth resistor, the anode of the second diode is grounded, and the other end of the nineteenth resistor is connected in series with the twentieth resistor and then connected to the second output terminal; the emitter of the second triode is respectively connected to one end of the twenty-first resistor and the second second resistor, the other end of the twenty-first resistor is connected to the control unit, and the other end of the twenty-second resistor is grounded; The second input terminal is connected in series with the twenty-third resistor and then connected to the base of the third transistor. The collector of the third transistor is connected to the second output terminal. The emitter of the third transistor is respectively connected to one end of the twenty-fourth resistor and the twenty-fifth resistor. The other end of the twenty-fourth resistor is connected to the control unit, and the other end of the twenty-fifth resistor is grounded.

7. The background suppression optoelectronic circuit according to claim 1, characterized in that: It also includes a power supply unit and a display unit, wherein the power supply unit is respectively connected to the power supply ends of the control unit, the transmitting tube and the driving unit, the light receiving tube and the operational amplifier unit, and the display unit; the input end of the display unit is also connected to the control unit.

8. The background suppression optoelectronic circuit according to claim 7, characterized in that: The power supply unit comprises a power supply chip, a first pin of the power supply chip is connected in series with a fifth capacitor and a sixth capacitor respectively and then grounded, and the first pin of the power supply chip is also connected to a power supply terminal; The second pin of the power supply chip is grounded; The third pin of the power supply chip is respectively connected to the seventh capacitor, the eighth capacitor and the negative electrode of the third diode and is grounded; the third pin is also connected to the twenty-sixth resistor, which is connected in series with the fourth diode and then connected to the power supply end.

9. The background suppression optoelectronic circuit according to claim 7, characterized in that: The display unit includes a fourth light emitting diode and a fifth light emitting diode, and the anode of the fourth light emitting diode is connected to the anode of the fifth light emitting diode; The cathode of the fourth light-emitting diode is connected in series with the twenty-seventh resistor and then connected to the control unit, and the cathode of the fifth light-emitting diode is connected in series with the twenty-eighth resistor and then connected to the control unit; the anode of the fourth light-emitting diode and the anode of the fifth light-emitting diode are also connected to the power supply terminal.

10. A photoelectric sensor, characterized in that: A background suppression photoelectric circuit as described in any one of claims 1 to 9 is used.

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