Through-beam light curtain, detection system, and installation and testing methods for through-beam light curtain.

Abstract

This invention provides a through-beam light curtain, a detection system, and a method for installing and detecting the through-beam light curtain. The transmitter of the through-beam light curtain controls a light-emitting diode (LED) to emit a detection beam via a control circuit; the receiver receives the detection beam via a receiving tube. During different scanning cycles in the detection working mode, the through-beam light curtain controls the LED to emit detection beams of different intensities via the control circuit; or controls the amplifier circuit to use different amplification factors, and controls an indicator unit to display the number of scanning cycles in which the receiving tube can receive the detection beam within a preset period. This invention utilizes the indicator unit to display the number of scanning cycles in which the receiving tube can successfully receive the detection beam emitted by the transmitter within a preset period. Based on this number, the installation position and angle of the receiver are adjusted to maximize the value of this number, achieving alignment between the LED and the receiving tube, eliminating deviations caused by welding, assembly, and installation, and improving the working condition of the through-beam light curtain.

Description

Technical Field

[0001] This invention relates to the field of industrial inspection, and in particular to a through-beam light curtain, an inspection system, and an installation and inspection method for the through-beam light curtain. Background Technology

[0002] A through-beam light curtain is a detection device used to check whether an object has entered a specific area. It is widely used in various mechanical equipment in industrial production. Its applications include detecting whether a human body or limb has entered a hazardous area, detecting whether a workpiece on a conveyor has reached a predetermined position, and measuring the dimensions of an object. A through-beam light curtain generally consists of a transmitter and a receiver, installed opposite each other at opposite ends of the area to be inspected. The transmitter contains multiple light-emitting tubes that emit multiple beams of light, while the receiver contains multiple receiving tubes, each corresponding to one of the light-emitting tubes in the transmitter and receiving the detection beam emitted by that tube. When there are more than one light-emitting tube in the transmitter, to avoid mutual interference, the light-emitting tubes in the transmitter usually operate in a periodic, alternating manner. That is, one light-emitting tube first emits a detection beam, and the corresponding receiving tube in the receiver attempts to receive this detection beam. After this, another light-emitting tube emits a detection beam, and the corresponding receiving tube in the receiver attempts to receive it. This cycle continues until all the light-emitting tubes in the transmitter have emitted detection beams, ending the current cycle. In the industry, the working cycle of illuminating all the LEDs in turn is usually called the scanning cycle of the through-beam light curtain. Within one scanning cycle, if all the receiving tubes in the receiver can successfully receive the detection beam emitted by the corresponding LED in the transmitter, it can be determined that no object has entered the detection range.

[0003] Through-beam light curtains rely on emitting and receiving specific detection beams to detect objects. Therefore, besides the distance between the transmitter and receiver, the most significant factor affecting their reliability is the external ambient light source. In real-world working environments, ambient light is often unavoidable. Lighting lamps or arc light from metal welding can become external noise sources for the through-beam light curtain. When the intensity of the ambient light received by the receiver in the through-beam light curtain exceeds a certain proportion of the intensity of the beam emitted by the transmitter, the receiver may misjudge the signal and incorrectly emit a detected object signal. Therefore, to ensure the reliable operation of the through-beam light curtain, the receiver's signal-to-noise ratio must be maximized. Obviously, with a constant ambient light source, the intensity of the beam emitted by the transmitter is highest only when all the light-emitting diodes in the transmitter are aligned with their corresponding receiving diodes in the receiver. Only then does the through-beam light curtain possess the strongest resistance to ambient light interference and the highest operational reliability. However, this seemingly simple requirement is not easy to achieve in practice. This is because, on the one hand, the installation distance between the transmitter and receiver of many through-beam light curtains is quite far, sometimes even reaching 50 meters or more. Even slight deviations in installation position and angle can lead to significant errors. On the other hand, there are also deviations in the soldering and assembly of the light-emitting tubes, receiving tubes, and circuit boards inside the transmitter and receiver. Precise alignment of the external components does not guarantee that the internal light-emitting tubes and receiving tubes will also be accurately aligned.

[0004] To improve alignment accuracy during installation, some through-beam light curtains on the market are equipped with dedicated installation alignment devices. These products have laser emitters installed on the transmitters or receivers. When installing the light curtain, the side with the laser emitter is installed first, then the laser emitter is turned on, and the other side is installed according to the laser beam indication. This method can indeed solve the problem of installation deviation to a certain extent, but it is powerless to address deviations caused by the soldering and assembly of internal components. When the detection range of the light curtain is relatively large, these deviations cannot be ignored. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention proposes a through-beam light curtain, a detection system, and an installation and detection method for the through-beam light curtain. The system can control the intensity of the detection beam emitted by the light-emitting diode in different scanning cycles through the control circuit in the transmitter, or adjust the receiving sensitivity of the receiver by changing the amplification factor of the amplifier circuit in the receiver. An indicator unit displays the number of scanning cycles in which the receiving tube can receive the detection beam emitted by the transmitter within a preset cycle. Based on this number, the installation position and angle of the receiver are adjusted to maximize the value of this number, achieving alignment between the light-emitting diode and the receiving tube. This eliminates deviations caused by welding, assembly, and installation, and improves the working condition of the through-beam light curtain.

[0006] To address the aforementioned problems, the present invention provides a technical solution as follows: a through-beam light curtain, comprising a transmitter and a receiver; the transmitter includes at least one light-emitting diode and a control circuit, the light-emitting diode being connected to the control circuit, and the transmitter controlling the light-emitting diode to emit a detection beam through the control circuit; the receiver includes at least one receiving tube, an amplification circuit connected to the receiving tube, and an indicator unit connected to the amplification circuit, the receiver receiving the detection beam through the receiving tube; the through-beam light curtain, in different scanning cycles of the detection working mode, controls the light-emitting diode to emit detection beams of different intensities through the control circuit; or controls the amplification circuit to use different amplification factors, and controls the indicator unit to display the number of scanning cycles in which the receiving tube can receive the detection beam within a preset period.

[0007] Furthermore, the number of light-emitting tubes and the number of receiving tubes are the same, and they are arranged one-to-one.

[0008] Furthermore, the display includes at least one of a display screen, a digital tube, and an indicator light.

[0009] Furthermore, the indicating unit also includes a counter, which is connected to the display and the receiving tube respectively. The indicating unit obtains the number of scan cycles that the receiving tube can receive the detection beam within a preset period through the counter.

[0010] Furthermore, the transmitter has 32 light intensity levels, and the control circuit controls the light-emitting tube to emit detection beams of 32 different intensities in the detection working mode.

[0011] Furthermore, the receiver has 32 magnification levels, and the amplification circuit uses 32 different magnification levels to amplify the detection beam emitted by the light-emitting tube in the transmitter during the detection operation mode.

[0012] Based on the same inventive concept, the present invention also proposes a detection system, which includes a conveying device and a beam light curtain as described above, wherein the conveying device is used to send an object into the detection area, and the beam light curtain is disposed outside the detection area to detect whether the object has entered the detection area.

[0013] Based on the same inventive concept, this invention proposes a method for detecting the installation position of a through-beam light curtain. The detection method is applied to the through-beam light curtain described above. The detection method includes: S101: controlling each of the light-emitting tubes to emit probe beams of different intensities during different scanning cycles of the detection working mode through the control circuit of the transmitter; or using different amplification factors during different scanning cycles of the detection working mode through the amplification circuit in the receiver; S102: the number of scanning cycles in which the receiver tube can receive the probe beam within a preset cycle output by the receiving indicator unit, and adjusting the installation position and angle of the receiver according to the number of cycles.

[0014] Furthermore, the indicating unit includes a display, which displays the number of times. The display includes at least one of a screen, a digital tube, and an indicator light.

[0015] Furthermore, the indicating unit also includes a counter, which is connected to the display and the amplification circuit respectively. The indicating unit obtains the number of scan cycles that the receiving tube can receive the detection beam within a preset period through the counter.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: it can control the light-emitting tube to emit detection beams of different intensities in different scanning cycles through the control circuit in the transmitter, or adjust the receiving sensitivity of the receiver by changing the amplification factor of the amplifier circuit in the receiver, and use the indicator unit to display the number of scanning cycles in which the receiving tube can receive the detection beam emitted by the transmitter within a preset cycle, thereby adjusting the installation position and angle of the receiver according to the number to maximize the value of the number, realizing the alignment of the light-emitting tube and the receiving tube, eliminating the deviation caused by welding, assembly and installation, and improving the working state of the through-beam light curtain. Attached Figure Description

[0017] Figure 1 This is a structural diagram of an embodiment of the through-beam light curtain of the present invention;

[0018] Figure 2 This is a structural diagram of a receiver embodiment of the through-beam light curtain of the present invention;

[0019] Figure 3 This is a structural diagram of an embodiment of the detection system of the present invention;

[0020] Figure 4 This is a flowchart of an embodiment of the method for detecting the installation position of the through-beam light curtain according to the present invention. Detailed Implementation

[0021] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0022] Please see Figure 1-2 ,in, Figure 1 This is a structural diagram of an embodiment of the through-beam light curtain of the present invention; Figure 2 This is a structural diagram of a receiver embodiment of the beam-emitting screen of the present invention. (See attached diagram.) Figure 1-2 The present invention provides a detailed description of the beam projection screen.

[0023] In this embodiment, the through-beam light curtain includes a transmitter and a receiver; the transmitter includes at least one light-emitting diode and a control circuit, the light-emitting diode is connected to the control circuit, and the transmitter controls the light-emitting diode to emit a detection beam through the control circuit; the receiver includes at least one receiving tube, an amplification circuit connected to the receiving tube, and an indicator unit connected to the amplification circuit, and the receiver receives the detection beam through the receiving tube; the through-beam light curtain controls the light-emitting diode to emit detection beams of different intensities in different scanning cycles of the detection working mode through the control circuit; or controls the amplification circuit to use different amplification factors, and controls the indicator unit to display the number of scanning cycles in which the receiving tube can receive the detection beam within a preset cycle.

[0024] In one specific embodiment, the probe beam is a light pulse.

[0025] In this embodiment, the number of light-emitting tubes and receiving tubes are the same, and they are paired one-to-one.

[0026] In this embodiment, all LEDs can be controlled by a single control circuit, or some LEDs can be controlled by a single control circuit. Alternatively, each control circuit can be connected to different LEDs, and the control signals emitted by each control circuit for adjusting the light intensity of the LEDs can be controlled by a processor, controller, and other devices.

[0027] Similarly, an amplifier circuit can be connected to multiple receiving tubes, or to some receiving tubes, or each amplifier circuit can be connected to a corresponding receiving tube; there are no limitations on this.

[0028] In this embodiment, the detection beam emitted by the light-emitting diode can be visible light, infrared light, ultraviolet light, or other invisible light, and is not limited thereto.

[0029] In this embodiment, the receiving tube can be a photoresistor, photodiode, phototransistor, and photosensitive sensor module, as well as a device that can convert the detection beam emitted by the light-emitting tube into an electrical signal.

[0030] In this embodiment, the control circuit controls the light-emitting diode to emit detection beams of multiple light intensity levels, and the indicator unit outputs the number of scan cycles that the receiver tube can receive within a preset period of the detection beam emitted by the transmitter. The installer can use this number to adjust the installation position and angle of the receiver and to know the receiver's margin of resistance to ambient light interference.

[0031] In one specific embodiment, the control circuit controls the LED to emit light at 32 intensity levels.

[0032] In other embodiments, the control circuit can also control the LED to emit light intensities of 16, 24, and other orders of magnitude.

[0033] In this embodiment, the receiver has 32 amplification levels in the detection mode. The amplification circuit uses 32 different amplification levels to amplify the electrical signal generated by the receiving tube due to the detection beam emitted by the light-emitting tube in the transmitter.

[0034] In this embodiment, the indicator unit includes a display, and the indicator unit displays the number of times on the display.

[0035] In other embodiments, the indicator unit may also display the position and number of the receiving tube corresponding to the number of times.

[0036] In this embodiment, the indicator unit can also display on the display the number of times that different receiving tubes can successfully receive the detection beam emitted by the corresponding light-emitting tube in each preset cycle. These data can reflect the differences in the receiving status of different receiving tubes, so that the installers can make adjustments more effectively.

[0037] In this embodiment, the display includes at least one of a display screen, a digital tube, and an indicator light.

[0038] In other embodiments, the indicator unit can also be connected to a device with a display screen, such as a computer or mobile phone, to transmit the count information to the device, and the device can display the number of scan cycles of the detection beam emitted by the light-emitting tube received by the receiving tube.

[0039] In this embodiment, the indicator unit further includes a counter, which is connected to the display and the receiving tube respectively. The indicator unit obtains the number of times the receiving tube can receive the detection beam emitted by the corresponding light-emitting tube within a preset period through the counter.

[0040] The through-beam light curtain of the present invention differs from the traditional through-beam light curtain in the following ways:

[0041] 1. Regarding the transmitter, the transmitter of a traditional through-beam light curtain can only control the light-emitting tube to turn on or off, but cannot control its light intensity. That is to say, when the light-emitting tube is lit, the light intensity is always at a fixed maximum. However, the transmitter of the through-beam light curtain using this technical solution can not only control the light-emitting tube to turn on or off, but also has a control circuit to control the light intensity of the light-emitting tube. In addition to setting the light-emitting tube to the maximum light intensity, it can also reduce the light intensity of the light-emitting tube in m levels.

[0042] 2. Regarding the receiver, the receiver's amplification circuit has multiple amplification factors. During the detection mode, the LED emits a probe beam of fixed intensity. The amplification circuit uses different amplification factors in different scan cycles to amplify the light pulses emitted by the LED received by the receiver. The receiver of the through-beam light curtain using this technical solution is equipped with an indicator unit. This unit indicates the number of scan cycles in which the receiver can correctly receive the probe beam emitted by the transmitter within a preset period (i.e., one detection cycle of the detection mode). The indicator unit can be independently set or can be an existing indicator unit on the receiver.

[0043] 3. The through-beam light curtain using this technical solution has two working modes: normal working mode and detection working mode, the latter of which is unique to this invention.

[0044] In normal operating mode, the working process of the beam curtain is the same as that of traditional products. The transmitter uses a fixed maximum light intensity to scan and light up each light tube in a cycle, while the receiver tube in the receiver continuously tries to receive the beam of light emitted by the transmitter's light tube and determines whether the beam of light is blocked by an object based on the reception result.

[0045] The working principle of the detection mode is as follows: when the relative position of the transmitter / receiver and the ambient light source remain unchanged, the light intensity of the LED in the transmitter or the amplification factor of the amplifier circuit will become two factors affecting the signal-to-noise ratio of the receiver. When one of these two factors is fixed, and the light intensity of the LED in the transmitter or the amplification factor of the amplifier circuit is increased, the signal-to-noise ratio of the receiver will also increase. At this time, the receiver will be more likely to receive the light beam emitted by the transmitter. Therefore, if the receiver can achieve complete and correct reception when the LED in the transmitter is operating at a certain light intensity or the amplifier circuit is operating at a certain amplification factor, then further increasing the light intensity of the LED or the amplification factor of the amplifier circuit will only make the reception process more reliable. In other words, the beam screen will have a stronger ability to resist external ambient light interference or slight changes in the position between the transmitter and the receiver.

[0046] In the detection mode, the beam-emitting curtain is detected using two different methods.

[0047] In the first detection method, the LEDs in the transmitter still operate in a scanning mode. Within a scan cycle, each LED is sequentially lit, and the light intensity of each LED remains constant within the same scan cycle. However, unlike the normal operating mode, the transmitter uses different light intensities in adjacent scan cycles. That is, the control circuit in the transmitter changes the light intensity of the LEDs after each scan cycle. For a transmitter with m intensity control levels, different light intensities are used to light the LEDs for m consecutive cycles. Only after traversing all m intensity levels (i.e., after one detection round) will the transmitter reuse the light intensity used in the first scan cycle of the previous detection round, and this process continues cyclically for each detection round. The receiver operates similarly in this mode, except that after every m scan cycles (i.e., after one detection round), the detection result is output on the indicator unit. This result shows how many scan cycles within that detection round successfully received the beam emitted by the transmitter.

[0048] The second detection method involves the transmitter's LEDs operating in a scanning mode. Within a single scan cycle, each LED is illuminated sequentially, and the luminous intensity remains constant regardless of whether the scan cycles are different or the same. However, unlike the normal operating mode, the amplification factor used by the amplifier circuit differs between adjacent scan cycles. This means the receiver's amplifier circuit changes its amplification factor after each scan cycle. For a receiver with n possible amplification factors, different amplification factors are used to amplify the signal generated by the probe beam within n consecutive cycles. Only after traversing all n amplification factors, i.e., after one detection cycle, will the receiver reuse the amplification factor used in the first scan cycle of the previous detection cycle, and this process continues cyclically through each detection cycle. After completing one detection cycle, the detection result is output on the indicator unit. This result shows how many scan cycles within that detection cycle were successfully received by the receiver from the transmitter's LEDs.

[0049] During the installation of the through-beam light curtain, it can be first set to detection mode. Then, the installation position and angle can be adjusted based on the real-time detection results on the receiver indicator unit. Assuming the through-beam light curtain's transmitter has 32 intensity levels or its amplifier circuit has 32 amplification factors, and at a certain installation position, the receiver shows that all receiving tubes can successfully receive signals in 10 scan cycles on a detection wheel, while after adjusting the installation position, the number of cycles with successful reception increases to 15. This means the adjusted installation position is more ideal than the original. After several adjustments, the installation position and angle with the most successful reception cycles can be found. Since the detection results show the actual reception effect, the adjustment process will simultaneously correct for installation deviations, internal component soldering, assembly deviations, and the effects of ambient light, ensuring the through-beam light curtain reaches its optimal working state.

[0050] Because the transmitter's LEDs always operate at maximum luminous intensity in normal working mode, meaning the receiver's signal-to-noise ratio (SNR) remains at its highest level, this detection mode, which reduces the transmitter's luminous intensity, can be used to evaluate the SNR margin of the detector beam under current ambient light conditions. If the number of successful reception cycles in the detection mode is low, it indicates a low SNR margin for the receiver. In this case, even slight changes in ambient light can lead to reception failure and misjudgment by the receiver. In such situations, measures to reduce ambient light interference should be considered, or a different type of through-beam curtain should be used. Conversely, if the number of successful reception cycles in the detection mode is high, it indicates that the through-beam curtain has a high anti-light interference margin and can be used with confidence.

[0051] This detection mode, which reduces the amplification factor of the amplifier circuit, can also be used to evaluate the sensitivity of the receiver of the through-beam curtain under the current ambient light conditions. If the number of successful reception cycles in the detection mode is low, it indicates that the receiver's sensitivity is insufficient. In this case, even slight displacement between the transmitter and receiver caused by external mechanical vibration may lead to reception failure and misjudgment by the receiver. In this situation, it is advisable to consider reducing the detection range or replacing it with a different model of through-beam curtain. Conversely, if the number of successful reception cycles in the detection mode is high, it indicates that the through-beam curtain has a high safety margin and can be used with confidence.

[0052] Beneficial effects: The through-beam light curtain of the present invention can control the light-emitting tube to emit detection beams of different intensities in different scanning cycles through the control circuit in the transmitter, or adjust the receiving sensitivity of the receiver by changing the amplification factor of the amplifier circuit in the receiver. The indicator unit displays the number of scanning cycles in which the receiver can successfully receive the detection beam emitted by the transmitter within a preset cycle. Based on this number, the installation position and angle of the receiver are adjusted to maximize the value of this number, thereby achieving alignment between the light-emitting tube and the receiver, eliminating deviations caused by welding, assembly and installation, and improving the working state of the through-beam light curtain.

[0053] Based on the same inventive concept, this invention also proposes a detection system, please refer to [link to relevant documentation]. Figure 3 , Figure 3 This is a structural diagram of an embodiment of the detection system of the present invention. (In conjunction with...) Figure 3 The detection system of the present invention will be described in detail.

[0054] In this embodiment, the detection system includes a conveying device and a beam light curtain as described in the above embodiment. The conveying device is used to send the object into the detection area, and the beam light curtain is set outside the detection area to detect whether the object has entered the detection area.

[0055] Beneficial effects: The detection system of the present invention can control the light-emitting tube to emit detection beams of different intensities in different scanning cycles through the control circuit in the transmitter, or adjust the receiving sensitivity of the receiver by changing the amplification factor of the amplifier circuit in the receiver. The indicator unit displays the number of scanning cycles in which the receiver can successfully receive the detection beam emitted by the transmitter within a preset cycle. Based on this number, the installation position and angle of the receiver are adjusted to maximize the value of this number, thereby achieving alignment between the light-emitting tube and the receiver, eliminating deviations caused by welding, assembly and installation, and improving the working state of the through-beam light curtain.

[0056] Based on the same inventive concept, this invention also proposes a method for detecting the installation position of a beam-emitting curtain. Please refer to [link / reference]. Figure 4 , Figure 4 This is a flowchart of an embodiment of the method for detecting the installation position of a beam projection curtain according to the present invention. (In conjunction with...) Figure 4 The detection method of the present invention will be described in detail.

[0057] The detection method of the present invention is applied to the through-beam light curtain as described in the above embodiments. The method for detecting the installation position of the through-beam light curtain includes:

[0058] S101: The transmitter's control circuit controls each LED to emit a detection beam of different intensity during different scan cycles in the detection mode; or the receiver's amplifier circuit uses different amplification factors during different scan cycles in the detection mode.

[0059] S102: The number of scan cycles that the receiving tube can receive within a preset period of the receiving indication unit output, and the installation position and angle of the receiver are adjusted according to the number of scan cycles.

[0060] In this embodiment, the through-beam light curtain includes a transmitter and a receiver; the transmitter includes at least one light-emitting diode and a control circuit, the light-emitting diode is connected to the control circuit, and the transmitter controls the light-emitting diode to emit a detection beam through the control circuit; the receiver includes at least one receiving tube, an amplification circuit connected to the receiving tube, and an indicator unit connected to the amplification circuit, and the receiver receives the detection beam through the receiving tube; the through-beam light curtain controls the light-emitting diode to emit detection beams of different intensities in different scanning cycles of the detection working mode through the control circuit; or controls the amplification circuit to use different amplification factors, and controls the indicator unit to display the number of scanning cycles in which the receiving tube can receive the detection beam within a preset period.

[0061] In one specific embodiment, the probe beam is a light pulse.

[0062] In this embodiment, the number of light-emitting tubes and receiving tubes are the same, and they are paired one-to-one.

[0063] In this embodiment, all LEDs can be controlled by a single control circuit, or some LEDs can be controlled by a single control circuit. Alternatively, each control circuit can be connected to different LEDs, and the control signals emitted by each control circuit for adjusting the light intensity of the LEDs can be controlled by a processor, controller, and other devices.

[0064] Similarly, an amplifier circuit can be connected to multiple receiving tubes, or to some receiving tubes, or each amplifier circuit can be connected to a corresponding receiving tube; there are no limitations on this.

[0065] In this embodiment, the detection beam emitted by the light-emitting diode can be visible light, infrared light, ultraviolet light, or other invisible light, and is not limited thereto.

[0066] In this embodiment, the receiving tube can be a photoresistor, photodiode, phototransistor, photosensitive sensor module, or other device capable of converting the detection beam emitted by the light-emitting tube into an electrical signal.

[0067] In this embodiment, the control circuit controls the light-emitting diode to emit detection beams of multiple light intensity levels, and the indicator unit outputs the number of scan cycles in which the receiver tube can successfully receive the detection beam emitted by the transmitter within a preset period. The installer can use this to adjust the installation position and angle of the receiver and to know the receiver's margin of resistance to ambient light interference.

[0068] In one specific embodiment, the control circuit controls the LED to emit light at 32 intensity levels.

[0069] In other embodiments, the control circuit can also control the LED to emit light intensities of 16, 24, and other orders of magnitude.

[0070] In this embodiment, the receiver has 32 amplification levels in the detection mode. The amplification circuit uses 32 different amplification levels to amplify the electrical signal generated by the receiving tube due to the detection beam emitted by the light-emitting tube in the transmitter.

[0071] In this embodiment, the indicator unit includes a display, and the indicator unit displays the number of times on the display.

[0072] In other embodiments, the indicator unit may also display the position and number of the receiving tube corresponding to the number of times.

[0073] In this embodiment, the indicator unit can also display on the display the number of times that different receiving tubes can successfully receive the detection beam emitted by the corresponding light-emitting tube in each preset cycle. These data can reflect the differences in the receiving status of different receiving tubes, so that the installers can make adjustments more effectively.

[0074] In this embodiment, the display includes at least one of a display screen, a digital tube, and an indicator light.

[0075] In other embodiments, the indicator unit can also be connected to a device with a display screen, such as a computer or mobile phone, to transmit the count information to the device, and the device can display the number of scan cycles of the detection beam emitted by the light-emitting tube received by the receiving tube.

[0076] In this embodiment, the indicator unit further includes a counter, which is connected to the display and the receiving tube respectively. The indicator unit obtains the number of times the receiving tube can receive the detection beam emitted by the corresponding light-emitting tube within a preset period through the counter.

[0077] The through-beam light curtain of the present invention differs from the traditional through-beam light curtain in the following ways:

[0078] 1. Regarding the transmitter, the transmitter of a traditional through-beam light curtain can only control the light-emitting tube to turn on or off, but cannot control its light intensity. That is to say, when the light-emitting tube is lit, the light intensity is always at a fixed maximum. However, the transmitter of the through-beam light curtain using this technical solution can not only control the light-emitting tube to turn on or off, but also has a control circuit to control the light intensity of the light-emitting tube. In addition to setting the light-emitting tube to the maximum light intensity, it can also reduce the light intensity of the light-emitting tube in m levels.

[0079] 2. Regarding the receiver, the receiver's amplification circuit has multiple amplification factors. During the detection mode, the LED emits a probe beam of fixed intensity. The amplification circuit uses different amplification factors in different scan cycles to amplify the light pulses emitted by the LED received by the receiver. The receiver of the through-beam light curtain using this technical solution is equipped with an indicator unit. This unit indicates the number of scan cycles in which the receiver can correctly receive all probe beams from the transmitter within a fixed period (i.e., one detection cycle of the detection mode). The indicator unit can be independently set or can be an existing indicator unit on the receiver.

[0080] 3. The through-beam light curtain using this technical solution has two working modes: normal working mode and detection working mode, the latter of which is unique to this invention.

[0081] In normal operating mode, the working process of the beam curtain is the same as that of traditional products. The transmitter uses a fixed maximum light intensity to scan and light up each light tube in a cycle, while the receiver tube in the receiver continuously tries to receive the beam of light emitted by the transmitter's light tube and determines whether the beam of light is blocked by an object based on the reception result.

[0082] The working principle of the detection mode is as follows: when the relative position of the transmitter / receiver and the ambient light source remain unchanged, the light intensity of the LED in the transmitter or the amplification factor of the amplifier circuit will become two factors affecting the signal-to-noise ratio of the receiver. When one of these two factors is fixed, and the light intensity of the LED in the transmitter or the amplification factor of the amplifier circuit is increased, the signal-to-noise ratio of the receiver will also increase. At this time, the receiver will be more likely to receive the light beam emitted by the transmitter. Therefore, if the receiver can achieve complete and correct reception when the LED in the transmitter is operating at a certain light intensity or the amplifier circuit is operating at a certain amplification factor, then further increasing the light intensity of the LED or the amplification factor of the amplifier circuit will only make the reception process more reliable. In other words, the beam screen will have a stronger ability to resist external ambient light interference or slight changes in the position between the transmitter and the receiver.

[0083] In the detection mode, the beam-emitting curtain is detected using two different methods.

[0084] In the first detection method, the LEDs in the transmitter still operate in a scanning mode. Within a scan cycle, each LED is sequentially lit, and the light intensity of each LED remains constant within the same scan cycle. However, unlike the normal operating mode, the transmitter uses different light intensities in adjacent scan cycles. That is, the control circuit in the transmitter changes the light intensity of the LEDs after each scan cycle. For a transmitter with m intensity control levels, different light intensities are used to light the LEDs for m consecutive cycles. Only after traversing all m intensity levels (i.e., after one detection round) will the transmitter reuse the light intensity used in the first scan cycle of the previous detection round, and this process continues cyclically for each detection round. The receiver operates similarly in this mode, except that after every m scan cycles (i.e., after one detection round), the detection result is output on the indicator unit. This result shows how many scan cycles within that detection round successfully received the beam emitted by the transmitter.

[0085] The second detection method involves the transmitter's LEDs operating in a scanning mode. Within a single scan cycle, each LED is illuminated sequentially, and the luminous intensity remains constant regardless of whether the scan cycles are different or the same. However, unlike the normal operating mode, the amplification factor used by the amplifier circuit differs between adjacent scan cycles. This means the receiver's amplifier circuit changes its amplification factor after each scan cycle. For a receiver with n possible amplification factors, different amplification factors are used to amplify the signal generated by the probe beam within n consecutive cycles. Only after traversing all n amplification factors, i.e., after one detection cycle, will the receiver reuse the amplification factor used in the first scan cycle of the previous detection cycle, and this process continues cyclically through each detection cycle. After completing one detection cycle, the detection result is output on the indicator unit. This result shows how many scan cycles within that detection cycle were successfully received by the receiver from the transmitter's LEDs.

[0086] During the installation of the through-beam light curtain, it can be first set to detection mode. Then, the installation position and angle can be adjusted based on the real-time detection results on the receiver indicator unit. Assuming the through-beam light curtain's transmitter has 32 intensity levels or its amplifier circuit has 32 amplification factors, and at a certain installation position, the receiver shows that all receiving tubes can successfully receive signals in 10 scan cycles on a detection wheel, while after adjusting the installation position, the number of cycles with successful reception increases to 15. This means the adjusted installation position is more ideal than the original. After several adjustments, the installation position and angle with the most successful reception cycles can be found. Since the detection results show the actual reception effect, the adjustment process will simultaneously correct for installation deviations, internal component soldering and assembly deviations, and the effects of ambient light, ensuring the through-beam light curtain reaches its optimal working state.

[0087] Because the transmitter's LEDs always operate at maximum luminous intensity in normal working mode, meaning the receiver's signal-to-noise ratio (SNR) remains at its highest level, this detection mode, which reduces the transmitter's luminous intensity, can be used to evaluate the SNR margin of the detector beam under current ambient light conditions. If the number of successful reception cycles in the detection mode is low, it indicates a low SNR margin for the receiver. In this case, even slight changes in ambient light can lead to reception failure and misjudgment by the receiver. In such situations, measures to reduce ambient light interference should be considered, or a different type of through-beam curtain should be used. Conversely, if the number of successful reception cycles in the detection mode is high, it indicates that the through-beam curtain has a high anti-light interference margin and can be used with confidence.

[0088] This detection mode, which reduces the amplification factor of the amplifier circuit, can also be used to evaluate the sensitivity of the receiver of the through-beam curtain under the current ambient light conditions. If the number of successful reception cycles in the detection mode is low, it indicates that the receiver's sensitivity is insufficient. In this case, even slight displacement between the transmitter and receiver caused by external mechanical vibration may lead to reception failure and misjudgment by the receiver. In this situation, it is advisable to consider reducing the detection range or replacing it with a different model of through-beam curtain. Conversely, if the number of successful reception cycles in the detection mode is high, it indicates that the through-beam curtain has a high safety margin and can be used with confidence.

[0089] Beneficial effects: The installation position detection method of the light-emitting curtain of the present invention can control the light-emitting tube to emit detection beams of different intensities in different scanning cycles through the control circuit in the transmitter, or adjust the receiving sensitivity of the receiver by changing the amplification factor of the amplifier circuit in the receiver. The indicator unit displays the number of scanning cycles in which the receiver tube can successfully receive the detection beam emitted by the transmitter in a preset cycle. Based on this number, the installation position and angle of the receiver are adjusted to maximize the value of this number, thereby achieving alignment between the light-emitting tube and the receiver tube, eliminating deviations caused by welding, assembly and installation, and improving the working state of the light-emitting curtain.

[0090] In the several embodiments provided by this invention, it should be understood that the disclosed devices, modules, and units can be implemented in other ways. For example, the device implementations described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or units may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0091] The components described as separate may or may not be physically separated. Similarly, the components shown may or may not be physically separate; they may be located in one place or distributed across multiple locations. Some or all of them can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0092] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A beam-through light curtain, characterized in that, The through-beam light curtain includes a transmitter and a receiver; The transmitter includes at least one light-emitting diode and a control circuit. The light-emitting diode is connected to the control circuit, and the transmitter controls the light-emitting diode to emit a detection beam through the control circuit. The receiver includes at least one receiving tube, an amplification circuit connected to the receiving tube, and an indicator unit connected to the amplification circuit. The receiver receives the detection beam through the receiving tube. The through-beam light curtain controls the light-emitting diode to emit detection beams of different intensities during different scanning cycles of the detection working mode via the control circuit; or controls the amplification circuit to use different amplification factors and controls the indicator unit to display the number of scanning cycles in which the receiving tube can receive the detection beam within a preset period. When the amplifier circuit is controlled to use different amplification factors, each of the light-emitting diodes will be lit sequentially in one scan cycle. The luminous intensity of each light-emitting diode remains constant in different scan cycles or in the same scan cycle. For a receiver with n amplification factors, the receiver tubes with different amplification factors are used to receive the signal generated by the probe beam in n consecutive cycles. After traversing all n amplification factors, that is, after one detection cycle, the detection result of this cycle is output on the indicator unit. The real-time detection result shows how many scan cycles the receiver can successfully receive the beam emitted by the light-emitting diode of the transmitter in the n scan cycles contained in this detection cycle. During the installation of the through-beam light curtain, the through-beam light curtain is first set to the detection working mode. Then, the installation position and angle are adjusted according to the real-time detection results on the receiver indicator unit. The adjustment process will simultaneously correct for installation deviations, internal component welding, assembly deviations and the effects of ambient light. Additionally, the signal-to-noise ratio margin of the probe beam under current ambient light conditions is evaluated by using a detection mode that reduces the emitter's luminous intensity mechanism.

2. The through-beam light curtain as described in claim 1, characterized in that, The number of light-emitting tubes and the number of receiving tubes are the same, and they are paired one-to-one.

3. The through-beam light curtain as described in claim 1, characterized in that, The indicator unit includes a display, which displays the number of scan cycles. The display includes at least one of a screen, a digital tube, and an indicator light.

4. The through-beam light curtain as described in claim 3, characterized in that, The indicating unit also includes a counter, which is connected to the display and the amplification circuit respectively. The indicating unit obtains the number of scan cycles that the receiving tube can receive the detection beam within a preset period through the counter.

5. The through-beam light curtain as described in claim 1, characterized in that, The transmitter has 32 light intensity levels, and the control circuit controls the light-emitting tube to emit 32 different intensity detection beams in the detection working mode.

6. The through-beam light curtain as described in claim 1, characterized in that, The receiver has 32 magnification levels, and the amplification circuit uses 32 different magnification levels to amplify the receiving tube to receive the detection beam emitted by the light-emitting tube in the transmitter in the detection working mode.

7. A detection system, characterized in that, The detection system includes a conveying device and a beam light curtain as described in any one of claims 1-6, wherein the conveying device is used to send an object into the detection area, and the beam light curtain is disposed outside the detection area to detect whether the object has entered the detection area.

8. A method for detecting the installation position of a through-beam light curtain, characterized in that, The detection method is applied to the through-beam light curtain as described in any one of claims 1-6, and the detection method includes: S101: The transmitter's control circuit controls each of the light-emitting diodes to emit a detection beam of different intensities during different scan cycles of the detection working mode; or the receiver's amplifier circuit uses different amplification factors during different scan cycles of the detection working mode. S102: The receiving tube can receive the number of scan cycles of the detection beam within a preset period of the output of the receiving indication unit, and the installation position and angle of the receiver are adjusted according to the number of scan cycles.

9. The method for detecting the installation position of the through-beam light curtain as described in claim 8, characterized in that, The indicator unit includes a display, which displays the number of scan cycles. The display includes at least one of a screen, a digital tube, and an indicator light.

10. The method for detecting the installation position of the through-beam light curtain as described in claim 9, characterized in that, The indicating unit also includes a counter, which is connected to the display and the amplification circuit respectively. The indicating unit obtains the number of scan cycles that the receiving tube can receive the detection beam within a preset period through the counter.

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