Automatic dimming system for welding helmet and method for controlling the darkness thereof

Abstract

The automatic light changing system comprises a filter with a liquid crystal box assembly (LCD) and a darkness control system, the control system comprising: a micro control unit (MCU); a detection unit, a parameter setting unit and a power supply control circuit electrically connected therewith, the detection unit detecting light signals under arc striking and arc extinguishing operations and converting the light signals into electrical signals and sending the electrical signals to the MCU; the setting unit sending working parameters to the MCU; the MCU generating an output control signal based on the electrical signals and the working parameters and sending the output control signal to the control circuit; and a driving circuit electrically connected to the control circuit downstream of the control circuit, the control circuit providing a control voltage required for driving the LCD to the driving circuit based on the control signal; the driving circuit driving the LCD to change between bright and dark states, within a time delay range after the arc extinguishing operation, a continuous darkness curve of the LCD is distributed in a time sequence as follows: a first stage with constant darkness; a second stage with decreasing darkness and rate of change; and a third stage with linearly distributed darkness. The application also relates to a welding mask comprising the automatic light changing system and a method for controlling darkness of the welding mask.

Description

Technical Field

[0001] This invention relates to the technical field of welding protection, specifically to an automatic dimming system with mixed time delay characteristics for welding masks. The invention also relates to a method for controlling the time delay and darkness of the automatic dimming system after a welding operation, and a welding mask including the automatic dimming system. Background Technology

[0002] In welding, smelting, glassmaking, ceramics, and mechanical heat processing, production workers are frequently exposed to high-temperature furnaces and kilns, with temperatures generally between 1050-2150 degrees Celsius, corresponding to short-infrared radiation of 0.78-3 micrometers. At these temperatures, approximately 70% or more of infrared radiation and a large amount of visible and ultraviolet light are generated. Ultraviolet radiation from welding can cause damage to the cornea and conjunctiva even with short-term exposure (most severe with 28nm light); the intense infrared radiation can easily cause lens opacity. Welding goggles effectively block these infrared and ultraviolet rays. These lenses are based on optical glass and use colorants such as iron oxide, cobalt oxide, and chromium oxide, with the addition of a certain amount of cerium oxide to increase ultraviolet absorption. They are green or yellowish-green in appearance. They completely block ultraviolet radiation, have an infrared transmittance of <5%, and a visible light transmittance of approximately 0.1%.

[0003] Ordinary protective goggles are non-adjustable. Adjustable light filters are typically used during welding, but for post-weld observation, they generally only provide a simple time delay of the welding protection darkness, with a fixed darkness setting, and suffer from large abrupt changes in darkness. Typical welding process darkness modes include... Figure 1 As shown, after the arc is extinguished, it maintains its original darkness for a certain delay before abruptly returning to a bright state. Therefore, it cannot flexibly adapt to changes in the temperature and light intensity of the molten pool during high-current, high-temperature welding.

[0004] In actual welding processes, there are typically two scenarios that are not very comfortable to use. One is high-current welding, where the workpiece remains illuminated for a long time after the arc is extinguished, requiring a large time delay. This can easily lead to the workpiece being difficult to see for a considerable period after the arc is extinguished. The second is rapid continuous spot welding, which requires a very small time delay. This can easily result in excessive contrast upon exiting the welding process, causing repeated eye strain and fatigue. Better time delay control methods are needed to solve these problems.

[0005] Currently, there are generally two methods to seek improvement. The first is for spot welding, where after the arc is extinguished, it immediately enters a fixed, lower darkness state, maintains this state for a period of time, and then returns to a bright state. Its darkness pattern is as follows: Figure 2 As shown; the second type is for the general situation, where, for a period of time after arc extinction, the darkness changes from the working darkness gradient at the time of arc extinction to the bright state, and its darkness pattern is as follows. Figure 3As shown. The first method can improve the contrast in rapid spot welding, but the transition after arc extinction is too abrupt and still easily dazzles the eyes. Moreover, it is ineffective for high-current welding workpieces with long illumination times. The second method requires a very short total time for rapid spot welding, which does not reduce the contrast. For high-current welding workpieces with long illumination times, the total time must be set longer. The speed at which the workpiece is seen is slightly faster than with the same delay and constant dimming, but it still requires a relatively long time.

[0006] It should be noted that the "Background Art" paragraph is only used to help understand the content of this invention. Therefore, the content disclosed in the "Background Art" paragraph may include some prior art that is not known to those skilled in the art. The content disclosed in the "Background Art" paragraph does not mean that the content or the problems to be solved by one or more embodiments of this invention were known or understood by those skilled in the art before this application was filed. Summary of the Invention

[0007] In view of the above-mentioned deficiencies in the prior art, it is necessary to provide an automatic brightness-changing system that can provide good protection after the arc is extinguished under various welding conditions, such as the long bright light retention time of the high current molten pool and continuous spot welding, and a method for controlling the time delay and darkness after the welding operation.

[0008] To achieve the above objectives, the present invention provides an automatic dimming system for welding masks, the automatic dimming system comprising an automatic dimming filter and a control system for controlling its darkness, the automatic dimming filter comprising a liquid crystal cell assembly, and the control system comprising:

[0009] Microcontroller unit;

[0010] The photoelectric sensor detection unit, which is electrically connected to the microcontroller unit, is used to detect the optical signals during arc initiation and arc extinguishing operations, convert them into electrical signals, and send the electrical signals to the microcontroller unit.

[0011] The operating parameter setting unit, which is electrically connected to the microcontroller unit, is used to send operating parameters to the microcontroller unit.

[0012] A liquid crystal power supply control circuit electrically connected to the microcontroller unit, wherein the microcontroller unit is capable of generating an output control signal based on the electrical signal and the operating parameters and sending it to the liquid crystal power supply control circuit; and

[0013] A liquid crystal driving circuit is electrically connected downstream of the liquid crystal power supply control circuit, wherein the liquid crystal power supply control circuit is capable of providing the control voltage required to drive the liquid crystal cell assembly to the liquid crystal driving circuit based on the output control signal from the microcontroller unit.

[0014] The liquid crystal driving circuit drives the liquid crystal cell assembly to switch between a bright state and a dark state, wherein within a certain time delay range after the arc extinguishing operation, the continuous darkness curve of the liquid crystal cell assembly is distributed in the following time sequence: in the first stage of the time delay range, the darkness remains unchanged; in the second stage of the time delay range, both the darkness and its rate of change decrease; and in the third stage of the time delay, the darkness maintains a linear distribution.

[0015] Preferably, the operating parameters are pre-set operating parameters when the automatic dimming system leaves the factory or operating parameters manually input by the operator based on actual working conditions. The operating parameters include the duration, starting darkness, and ending darkness of each stage of the delay range.

[0016] Preferably, the duration of the first stage is adjustable between 0 and 1000 milliseconds, and the initial darkness and the final darkness of the first stage are the first darkness of the liquid crystal cell assembly during the arc extinguishing operation.

[0017] Preferably, the duration of the second stage is adjustable between 100 and 300 milliseconds, the initial darkness of the second stage is the first darkness of the liquid crystal cell assembly during the arc extinguishing operation, and the final darkness of the second stage is a second darkness that is smaller than the first darkness.

[0018] Preferably, the duration of the third stage is adjustable between 0 and 2 seconds, the starting darkness of the third stage is the ending darkness of the second stage, and the ending darkness of the third stage is not greater than the starting darkness of the third stage and not less than the bright state darkness of the liquid crystal cell assembly.

[0019] Preferably, the first darkness level is between DIN 8 and 15, and the second darkness level is between DIN 3 and 7.

[0020] Preferably, the liquid crystal power supply control circuit includes a first liquid crystal power supply control circuit and a second liquid crystal power supply control circuit, and the automatic dimming system further includes a switching switch that selectively connects to the first liquid crystal power supply control circuit and the second liquid crystal power supply control circuit, wherein the first liquid crystal power supply control circuit is connected to the switching switch in the first stage to provide the control voltage to the liquid crystal driving circuit; and the second liquid crystal power supply control circuit is connected to the switching switch in the second stage and the third stage to provide the control voltage to the liquid crystal driving circuit.

[0021] Preferably, the liquid crystal power supply control circuit includes at least one of a digital-to-analog converter module, a pulse width modulation module, and an RC discharge module.

[0022] Preferably, the output control signal includes information about the control voltage for driving the liquid crystal cell assembly at different timings within the time delay range, wherein the control voltage of the first stage is greater than the control voltage of the entire second stage, and the control voltage at the end of the second stage is greater than the control voltage of the third stage.

[0023] According to another aspect of the present invention, a welding mask is provided, comprising: a mask body and an automatic dimming system as described above, wherein an automatic dimming filter in the automatic dimming system is mounted at the front opening of the mask body, and a control system in the automatic dimming system is integratedly mounted on the mask body.

[0024] According to another aspect of the present invention, a method for controlling the darkness of an automatic dimming system for welding masks is provided, comprising the following steps:

[0025] Provide the automatic dimming system as described above;

[0026] The working mode of the automatic dimming system is set to the hybrid time delay mode via the working parameter setting unit, and the corresponding working parameters are sent to the micro control unit.

[0027] The photoelectric sensor detection unit is used to detect the optical signals during arc initiation and arc extinguishing operations, convert the optical signals into electrical signals, and send them to the microcontroller unit.

[0028] When the microcontroller receives an electrical signal indicating an arc extinguishing operation, the microcontroller sends an output control signal generated based on the operating parameters to the liquid crystal power supply control circuit.

[0029] The liquid crystal power supply control circuit provides the control voltage required to drive the liquid crystal cell assembly to the liquid crystal driving circuit based on the output control signal from the microcontroller unit; and

[0030] The liquid crystal driving circuit drives the liquid crystal cell assembly to switch between a bright state and a dark state. The magnitude and duration of the control voltage are configured such that, within a certain time delay after the arc extinguishing operation, the continuous darkness curve of the liquid crystal cell assembly is distributed in the following time sequence: in the first stage of the time delay, the darkness remains constant; in the second stage of the time delay, both the darkness and its rate of change decrease; and in the third stage of the time delay, the darkness maintains a linear distribution.

[0031] Preferably, the liquid crystal power supply control circuit adjusts the control voltage by means of at least one of digital-to-analog conversion, pulse width modulation, and RC discharge. Attached Figure Description

[0032] The above and other aspects of the present invention will now be understood and appreciated more thoroughly in conjunction with the accompanying drawings, wherein:

[0033] Figure 1 This is a schematic diagram of the dark mode in a typical welding process according to existing technology;

[0034] Figure 2 This is a schematic diagram of a specific dark mode after welding, which is an improvement on spot welding operations in the prior art.

[0035] Figure 3 This is a schematic diagram of a specific dark mode after welding, which is an improvement on general operations in the prior art;

[0036] Figure 4 This is a schematic diagram of the dark mode of the optimized welding process according to a preferred embodiment of the present invention;

[0037] Figure 5 A schematic block diagram of an automatic dimming system with hybrid time delay characteristics according to the present invention;

[0038] Figure 6 It shows Figure 5 Another alternative to the LCD power supply control circuit used in the automatic dimming system;

[0039] Figure 7 This is a schematic diagram of a welding mask equipped with an automatic dimming system with hybrid time delay characteristics according to the present invention;

[0040] Figure 8 A flowchart illustrating the operation of an automatic dimming system with hybrid time delay characteristics according to the present invention. Detailed Implementation

[0041] To make the technical problems to be solved, the technical solutions, and the beneficial technical effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and exemplary embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Unless otherwise expressly stated in the drawings, the dimensions, positions, and any distances between components, features, elements, etc., are not necessarily drawn to scale and may be disproportionate and / or exaggerated for clarity.

[0042] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be recognized that the terms “comprising,” “including,” and / or “constituting,” when used in this specification, specify the presence of the stated feature, integer, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. Unless otherwise indicated, when enumerating ranges of values, the upper and lower limits of that range, as well as any subranges therebetween, are included. Unless otherwise stated, terms such as “first,” “second,” etc., are used only to distinguish one element from another. For example, one element may be referred to as “first element,” and similarly, another element may be referred to as “second element,” and vice versa. Paragraph headings used herein are for organizational purposes only and should not be construed as limiting the described subject matter.

[0043] Unless explicitly indicated otherwise, the terms “about,” “approximately,” “substantially,” etc., mean that quantities, dimensions, formulations, parameters, and other quantities and characteristics are not and need not be precise, but may be approximate and / or larger or smaller as required.

[0044] Unless expressly indicated otherwise, all connections and all operational connections may be direct or indirect. Similarly, unless expressly indicated otherwise, all connections and all operational connections may be rigid or non-rigid. Furthermore, in this invention, the term "connection" includes not only mechanical connections but also electrical connections and communicative couplings between components and / or modules.

[0045] Similar reference numerals are used throughout the text to refer to similar elements. Therefore, identical or similar reference numerals may be used in the description with reference to other figures, even if they are neither mentioned nor described in the corresponding figures. Furthermore, even elements not denoted by reference numerals may be described with reference to other figures.

[0046] In response to the aforementioned problems mentioned in the background art, this invention proposes a hybrid time delay control method for the change in liquid crystal darkness after arc extinction, as well as an automatic light-changing system and welding mask that can support hybrid time delay function.

[0047] Reference Figure 4 This illustrates a schematic diagram of the dark mode of the optimized welding process according to a preferred embodiment of the present invention. Figures 1 to 3 Compared with the dark mode used in the prior art, the automatic dimming system of the present invention divides the dark changes and their delays after welding into three types according to the time sequence: basic delay, transition delay and gradual change delay, thereby realizing the splicing of the above three types of delays and the connection of the corresponding three stages of dark changes.

[0048] The following combination Figure 4 The three types of time delay stages are described in detail. It should be noted that the vertical axis in the figure shows the industry-defined DIN darkness (i.e., shading number). The closer to the dark state, the greater the DIN darkness (corresponding to lower light transmittance); conversely, the closer to the bright state, the smaller the DIN darkness (corresponding to higher light transmittance). First, the time from the start of the arc extinguishing operation is the first stage (basic time delay stage t1). The duration of this stage is adjustable between 0 and 1000 milliseconds. During this stage, the darkness / shading number is maintained at the moment of arc extinguishing (typically between DIN 8 and 15). That is, the initial darkness and the final darkness D1 of this stage remain consistent with the darkness D0 at the moment of arc extinguishing (e.g., DIN 11), thus meeting the protection requirements for the ultra-bright stage of the weld pool immediately after arc extinguishing. Next, immediately after the first stage ends, the second stage (transition delay stage t2) begins. The duration of this stage is adjustable between 100 and 300 milliseconds (e.g., 200 milliseconds in a preferred embodiment). The darkness transitions from the end darkness D1 of the base delay to a second darkness D2 (typically between DIN3 and 7, e.g., DIN5.5 in the illustrated preferred embodiment) that is lower than the end darkness of the base delay. Figure 3 Compared to the gradual transition from the initial darkness of the arc-extinguishing working state to the bright state, the rate of change of darkness over time decreases in the second stage of this invention. That is, in the second stage, the closer time gets to the start point of the transition delay (i.e., the end point of the base delay), the greater the rate of change of darkness at that point (shown as a steeper darkness change curve in the figure), and the smaller the rate of change of darkness at the corresponding point (shown as a flatter darkness change curve in the figure) as time gradually approaches the end point of the transition delay. Through this setting, a comfortable transition between darkness in the base delay stage and the gradually changing delay stage (described below) can be met, solving the problem of visual discomfort caused by a precipitous drop in darkness and quickly achieving a state where the workpiece operating environment is clearly observable. Finally, after the second stage ends, the third stage (gradually varying delay stage t3) begins. The duration of this stage is adjustable between 0 and 3 seconds (in a preferred embodiment, for example, 2 seconds). The darkness linearly transitions from the end darkness D2 of the transition delay to the following darkness (i.e., the end darkness D3 of the third stage), wherein the end darkness of this third stage is not greater than the end darkness of the transition delay and not less than the darkness corresponding to the bright state of the liquid crystal cell assembly of the auto-dimming filter (typically DIN3~4). Figure 4Taking the dark mode shown as an example, the ending darkness D3 of the third stage is between the ending darkness D2 of the second stage and the bright-state darkness D4 of the liquid crystal cell assembly. However, those skilled in the art will understand that the third darkness has the following two limits: when the third darkness is equal to the ending darkness D2 of the second stage, the entire third stage is equivalent to maintaining the ending darkness of the second stage unchanged (e.g., Figure 4 (As shown by the dashed line I); and when the third darkness is equal to the bright-state darkness D4 of the liquid crystal cell assembly, the darkness change curve of the third stage is as follows. Figure 4 As shown by the dashed line II. By setting the third stage (gradual change stage) as described above, a certain level of darkness can be maintained before the liquid crystal cell assembly enters the bright state, which can both protect the operator's eyes from strong light stimulation and ensure that the operator can clearly observe the workpiece environment.

[0049] The following describes the automatic light-changing system that implements the hybrid time-delay concept of this invention from a hardware perspective. (Refer to...) Figure 5 The figure shows a schematic block diagram of an automatic dimming system according to the present invention. As shown, the automatic dimming system includes an automatic dimming filter 10 (for simplicity, the automatic dimming filter is symbolically represented by the liquid crystal cell assembly LCD in the block diagram, omitting filters for infrared and ultraviolet light filtering, etc.) and a control system 20 that controls the darkness / shielding signal of the automatic dimming filter 10. The control system 20 includes a microcontroller unit (MCU), a photoelectric sensor detection unit 201 electrically connected to the MCU, a working parameter setting unit 202, a liquid crystal power supply control circuit 203, and a liquid crystal driving circuit 204 electrically connected downstream of the liquid crystal power supply control circuit 203. The photoelectric sensor detection unit 201 detects light signals during arc initiation and arc extinguishing operations, converts them into electrical signals, and sends the electrical signals to the MCU. The working parameter setting unit 202 sends working parameters to the MCU. In this invention, the MCU can receive working parameters preset or input from the working parameter setting unit 202 in standby mode. The pre-set or input working parameters include welding parameters such as darkness control parameters, sensitivity control parameters, and time delay control parameters, as well as working mode parameters such as grinding, welding, and cutting. Those skilled in the art will understand that preset values ​​for the base delay, transition delay, and gradual change delay can be pre-set at the factory for different working modes, including the duration of each delay stage and the darkness value at the beginning and end of each delay stage. This allows for automatic execution of tasks such as grinding, welding, and cutting according to the preset values ​​in the required working mode. Figure 4The hybrid delay control is shown. However, the invention is not limited to this; the operator can also manually set the relevant parameters according to the actual working conditions before the welding operation. Furthermore, the microcontroller unit (MCU) can generate an output control signal based on the electrical signal from the photoelectric sensor detection unit 201 and the preset or input working parameters from the working parameter setting unit 202, and send it to the liquid crystal power supply control circuit 203. The liquid crystal power supply control circuit 203 then provides the control voltage required to drive the liquid crystal cell assembly (LCD) to the liquid crystal driving circuit 204 based on the output control signal from the MCU. In practical operation, the liquid crystal power supply control circuit 203 sends the driving signal representing the corresponding control voltage for different time periods to the liquid crystal driving circuit 204, and then the liquid crystal driving circuit 204 applies the corresponding control voltage to the liquid crystal cell assembly LCD of the automatic light-changing filter 10. The transmittance of light in the dark state is adjusted by the orientation change of liquid crystal molecules in the liquid crystal cell to obtain the desired darkness, and the liquid crystal cell assembly LCD switches between the bright state and the dark state. This achieves a high level of darkness in the time delay range immediately following the arc extinguishing operation to protect the operator's eyes from the stimulation of the bright molten pool, and a gradually decreasing darkness after a long period of time to ensure that the operator can clearly observe the welding workpiece and the surrounding environment.

[0050] from Figure 5As shown in the preferred embodiment, the liquid crystal power supply control circuit 203 is implemented by a single circuit. This circuit provides a constant control voltage in the first stage, a control voltage that changes rapidly initially and then gradually decreases in rate of change in the second stage, and a control voltage that maintains a linear distribution of darkness in the liquid crystal cell assembly (LCD) in the third stage. It should be noted that for commonly used auto-dimming filters 10, the modular liquid crystal cell assembly (LCD) typically uses a positive liquid crystal film sandwiched between a polarizer and an analyzer. That is, when the driving voltage is 0 (i.e., no power is applied), the liquid crystal cell assembly (LCD) is in a bright state in standby mode; while as the driving voltage increases, the liquid crystal cell assembly (LCD) is in a dark state during operation, and the darkness value gradually increases. In an embodiment of the present invention, within a certain time delay range after the arc extinguishing operation, the control voltage required to drive the liquid crystal cell assembly LCD provided by the liquid crystal power supply control circuit 203 to the liquid crystal driving circuit 204 changes as follows: the control voltage in the first stage (i.e., the basic time delay stage) of the time delay range is greater than the control voltage of the entire second stage (i.e., the transition time delay stage) so that the darkness value of the first stage (usually between DIN8 and 15) is greater than the darkness value of the second stage (transitioning from the initial DIN8 to 15 to DIN3 to 7), and the control voltage at the end of the second stage is greater than the control voltage of the third stage (i.e., the gradual change time delay stage) so that the darkness value of the liquid crystal cell assembly LCD further decreases to near or reach the brightness state darkness (between DIN3 and 4) after entering the third stage. It should be noted that in practical operation, it is necessary to ensure that the ending darkness at the second stage is not lower than the final brightness state darkness. Therefore, when the above two darkness values ​​have overlapping ranges or the same endpoint values, it means that the brightness state of the automatic dimming filter 10 under normal standby is reached when the second stage ends. In other words, the darkness in the bright state will remain unchanged throughout the third stage so that the darkness in this stage still follows a linear distribution.

[0051] Furthermore, Figure 6 An alternative embodiment of the liquid crystal power supply control circuit implemented by two circuits is shown (details omitted for clarity). Figure 5(Partial modules in the system). Therefore, the control system also includes a switching switch 205. In the first stage, the first liquid crystal power supply control circuit 2031 is connected to the switching switch 205 to provide a constant control voltage; in the second stage, the second liquid crystal power supply control circuit 2032 is switched on to the switching switch 205, so that the second liquid crystal power supply control circuit 2032 provides a control voltage that initially changes rapidly and then the rate of change gradually decreases; further, in the third stage, the second liquid crystal power supply control circuit 2032 continues to provide a control voltage that maintains a linear distribution of the darkness of the liquid crystal cell assembly (LCD). It should be noted that the gradual or slow change in the darkness of the liquid crystal cell assembly by each liquid crystal power supply control circuit can be achieved by means of, but not limited to, the following: DAC (digital-to-analog) conversion, PWM (pulse width modulation) adjustment, and RC (resistance-capacitor) discharge. Therefore, the liquid crystal power supply control circuit of the present invention includes at least one of a digital-to-analog conversion module, a pulse width modulation module, and an RC discharge module. The principles and methods of adjusting the control voltage are well known to those skilled in the art and will not be described in detail here.

[0052] Furthermore, Figure 7 A general schematic diagram of a welding mask according to the present invention is shown, the welding mask including a mask body 30 and an automatic light-changing system as described above, wherein the mask body 30 is for connection with a headband structure (not shown) for wearing on the operator's head. Further as shown, an automatic light-changing filter 10 is mounted at the front opening of the mask body 30 such that, when worn by the operator, the liquid crystal cell assembly (LCD) of the automatic light-changing filter 10 is aligned with the operator's eyes, and a control system 20 is integratedly mounted on the mask body 30.

[0053] The following combination Figure 8 A brief description of the workflow of the automatic dimming system with hybrid time delay characteristics according to the present invention is provided. First, in the system standby state (S101), the working mode of the automatic dimming system is set to hybrid time delay mode via the working parameter setting unit 202. Then, as needed, factory-preset working parameters or working parameters manually input by the operator based on actual working conditions are sent to the microcontroller unit (MCU). These working parameters include, but are not limited to, working darkness, sensitivity, and basic time delay. For parameter input and display, the working parameter setting unit 202 preferably uses a selection button to input the working parameters to be adjusted and displays the adjusted working parameters via an LED screen display device. Those skilled in the art can also anticipate using a knob, resistive or capacitive touchscreen, etc., to adjust the working parameters. As described above, for the automatic dimming filter 10, which typically uses a positive liquid crystal cell assembly, the display is bright in the standby state (see [link to documentation]). Figure 4(The leftmost part of the schematic diagram) is used to facilitate the operator's observation of the workpiece to be welded and its surrounding working environment. Next, at S102, the photoelectric sensor detection unit 201 performs arc ignition detection. If the ambient light does not change, it indicates that the operator has not yet started the welding operation, and the system returns to the initial standby state to continue arc ignition detection. When arc welding occurs, the photoelectric sensor in the photoelectric sensor detection unit 201 detects the change in ambient light. After processing by the operational amplifier, the photoelectric sensor detection unit 201 converts the detected light signal into an arc ignition electrical signal and sends it to the microcontroller unit (MCU). In this case, the system enters... Figure 8 In the welding process control step S103 shown, the microcontroller unit (MCU) can adjust the darkness of the automatic dimming filter 10 based on the detected intensity of the welding arc light or based on user-defined or input settings. The MCU may include a microcontroller. During operation, the microcontroller reads the user-preset or input operating parameters and sends corresponding output control signals to the liquid crystal power supply control circuit 203. This causes the liquid crystal driving circuit 204 to apply a corresponding control voltage to the liquid crystal cell assembly (LCD) to adjust the darkness of the welding arc light after passing through the automatic dimming filter 10, thus protecting the operator's eyes from harm (see [link to relevant documentation]). Figure 4 The diagram illustrates the welding ultraviolet and infrared protection stages. Next, in step S104, the photoelectric sensor detection unit 201 initiates arc extinguishing detection (i.e., determining whether the welding operation has ended). If the photoelectric sensor detection unit 201 does not detect a light signal indicating arc extinguishing, it means the welding operation has not yet ended, and therefore returns to the previous steps to repeat normal welding process control. If the photoelectric sensor detection unit 201 detects a light signal indicating arc extinguishing, it converts it into an arc extinguishing electrical signal and sends it to the microcontroller unit (MCU). In this case, the process proceeds to... Figure 8 The darkness control step S105 is shown. As previously explained, at this time, the microcontroller unit (MCU) generates an output control signal based on the operating parameters (including the duration of each stage of the delay range, the initial darkness, and the final darkness) previously preset or input via the operating parameter setting unit 202, and sends it to the liquid crystal power supply control circuit 203. It is understood that the output control signal at this time includes information about the control voltage for driving the liquid crystal cell assembly (LCD) at different timings within a certain delay range after the arc extinguishing operation. Furthermore, the liquid crystal power supply control circuit 203 provides the control voltage required to drive the liquid crystal cell assembly (LCD) to the liquid crystal driving circuit 204, and drives the liquid crystal cell assembly (LCD) via the liquid crystal driving circuit 204, so that the darkness distribution presented after passing through the automatic dimming filter 10 after the arc extinguishing operation has the following characteristics: Figure 4 The characteristics of the mixed delay are shown, and it eventually returns to the bright state in the standby state.

[0054] In summary, by adopting the technical solution of this invention, the hybrid delay design not only solves the waiting problem caused by the excessively long holding time of high current bright light, but also meets the requirement of rapid observation in rapid spot welding, and avoids eye discomfort caused by excessive dark contrast, thus having great practical value.

[0055] It should be noted that the above explanation and illustration of the principles of the present invention are merely illustrative of preferred embodiments. However, the present invention is not limited to the specific structures described in the preferred embodiments, and various modifications are possible.

[0056] For example, in the preferred embodiments described above, the process of implementing the hybrid delay function of the present invention is illustrated by taking one liquid crystal power supply control circuit and switching between two liquid crystal power supply control circuits using a switching switch 205 as examples. However, those skilled in the art will understand that corresponding liquid crystal power supply control circuits can be set for the three different types of delay stages in the hybrid delay, thereby switching between three liquid crystal power supply control circuits to achieve the function of the present invention.

[0057] In addition, Figure 4 In the schematic diagram of the optimized welding process darkness mode according to a preferred embodiment of the present invention, the darkness of the entire first stage (i.e., the first darkness D1) remains unchanged from the darkness D0 at the moment the welding arc is extinguished. However, those skilled in the art will understand that the magnitude of the first darkness D1 can be artificially set as needed, so that it is higher or lower than the darkness D0 at the moment the arc is extinguished.

[0058] Furthermore, the present invention is explained and described using only a single liquid crystal cell assembly as an example in the preferred embodiments and accompanying drawings. Those skilled in the art will recognize that any number of modular liquid crystal cell assemblies can be set according to actual needs, and a corresponding number of liquid crystal driving circuits can be used to drive different liquid crystal cell assemblies respectively.

[0059] The above description, with reference to the accompanying drawings, details feasible but non-limiting embodiments of the automatic dimming system and its darkness control method according to the present invention. Modifications and additions to the technology and structure, as well as recombinations of features in the various embodiments, should be considered within the scope of the invention by those skilled in the art without departing from the scope and spirit of this disclosure as set forth in the following claims. Therefore, such modifications and additions conceivable under the teachings of this invention should be considered part of this disclosure. The scope of this disclosure is defined by the following appended claims and includes equivalent technologies known at the filing date of this disclosure and equivalent technologies not yet foreseen.

Claims

1. An automatic shade changing system for a welding helmet, characterized by, The automatic dimming system comprises an automatic dimming filter (10) and a control system for controlling the darkness of the automatic dimming filter (10), the automatic dimming filter (10) comprises a liquid crystal cell assembly (LCD), the control system comprises: a micro control unit (MCU); a photoelectric sensor detection unit (201) electrically connected to the micro control unit (MCU), for detecting and converting a light signal under an arc striking and extinguishing operation into an electric signal and sending the electric signal to the micro control unit (MCU); a working parameter setting unit (202) electrically connected to the micro control unit (MCU), for sending a working parameter to the micro control unit (MCU); a liquid crystal power supply control circuit (203) electrically connected to the micro control unit (MCU), the micro control unit (MCU) can generate an output control signal based on the electric signal and the working parameter and send the output control signal to the liquid crystal power supply control circuit (203); and a liquid crystal driving circuit (204) electrically connected to the liquid crystal power supply control circuit (203) downstream of the liquid crystal power supply control circuit (203), wherein the liquid crystal power supply control circuit (203) can provide a control voltage required for driving the liquid crystal cell assembly (LCD) to the liquid crystal driving circuit (204) based on the output control signal from the micro control unit (MCU); the liquid crystal driving circuit (204) drives the liquid crystal cell assembly (LCD) to change between a bright state and a dark state, wherein within a time delay range after the arc extinguishing operation, the continuous darkness curve of the liquid crystal cell assembly (LCD) is distributed in time as follows: in a first stage of the time delay range, the darkness is maintained unchanged; in a second stage of the time delay range, both the darkness and its change rate decrease; and in a third stage of the time delay, the darkness is maintained linearly distributed.

2. The automatic shading system of claim 1, wherein, The working parameter is a working parameter pre-set when the automatic dimming system is shipped or a working parameter manually input by an operator based on actual working conditions, and the working parameter comprises a duration of each stage of the time delay range, a starting darkness and an ending darkness.

3. The automatic shading system of claim 2, wherein, The duration of the first stage is adjustable between 0 and 1000 milliseconds, and the starting darkness and the ending darkness of the first stage are a first darkness of the liquid crystal cell assembly (LCD) when the arc extinguishing operation is performed.

4. The automatic shading system of claim 2, wherein, The duration of the second stage is adjustable between 100 and 300 milliseconds, the starting darkness of the second stage is the first darkness of the liquid crystal cell assembly (LCD) when the arc extinguishing operation is performed, and the ending darkness of the second stage is a second darkness smaller than the first darkness.

5. The automatic shading system of claim 2, wherein, The duration of the third stage is adjustable between 0 and 2 seconds, the starting darkness of the third stage is the ending darkness of the second stage, and the ending darkness of the third stage is not greater than the starting darkness of the third stage and not less than a bright state darkness of the liquid crystal cell assembly (LCD).

6. The automatic light varying system according to claim 4, characterized in that, The first darkness is between DIN 8 and 15, and the second darkness is between DIN 3 and 7.

7. The automatic shading system according to any one of claims 1 to 6, characterized in that, The liquid crystal power supply control circuit comprises a first liquid crystal power supply control circuit (2031) and a second liquid crystal power supply control circuit (2032), and the automatic dimming system further comprises a switch (205) selectively connected with the first liquid crystal power supply control circuit (2031) and the second liquid crystal power supply control circuit (2032), wherein the first liquid crystal power supply control circuit (2031) is connected with the switch (205) in the first stage to provide the control voltage to the liquid crystal driving circuit (204); and the second liquid crystal power supply control circuit (2032) is connected with the switch (205) in the second stage and the third stage to provide the control voltage to the liquid crystal driving circuit (204).

8. The automatic shading system according to any one of claims 1 to 6, characterized in that, The liquid crystal power supply control circuit comprises at least one of a digital-to-analog conversion module, a pulse width modulation module and an RC discharge module.

9. The automatic shading system according to any one of claims 1 to 6, characterized in that, The output control signal comprises information about the control voltage for driving a liquid crystal cell assembly (LCD) at different timings within the time delay range, the control voltage in the first stage is greater than the control voltage in the entire second stage, and the control voltage at the end of the second stage is greater than the control voltage in the third stage.

10. A welding helmet characterized by, Comprise: A mask body (30) and an automatic dimming system according to any one of claims 1 to 9, wherein the automatic dimming filter (10) in the automatic dimming system is installed at the front opening of the mask body (30), and the control system in the automatic dimming system is integrally installed in the mask body (30).

11. A method for controlling the darkness of an automatic dimming system for a welding mask, comprising the steps of: providing an automatic dimming system according to any one of claims 1 to 6; setting the working mode of the automatic dimming system to a mixed time delay mode via the working parameter setting unit (202), and sending the corresponding working parameters to the micro control unit (MCU); detecting the light signal under the arc striking and extinguishing operation by using the photoelectric sensor detection unit (201), converting the light signal into an electric signal and sending it to the micro control unit (MCU); when the micro control unit (MCU) receives the electric signal representing the arc extinguishing operation, the micro control unit (MCU) sends the output control signal generated based on the working parameters to the liquid crystal power supply control circuit (203); the liquid crystal power supply control circuit (203) provides the control voltage required for driving the liquid crystal cell assembly (LCD) to the liquid crystal driving circuit (204) based on the output control signal from the micro control unit (MCU); and The liquid crystal driving circuit (204) drives the liquid crystal cell assembly (LCD) to switch between bright state and dark state, the magnitude and duration of the control voltage are configured such that within a time delay range after arc extinguishing operation, the continuous dimming curve of the liquid crystal cell assembly (LCD) is distributed in time sequence as follows: in the first stage of the time delay range, the dimming is maintained unchanged; in the second stage of the time delay range, both the dimming and its rate of change are decreasing; and in the third stage of the time delay, the dimming is maintained linearly distributed.

12. The method of claim 11, wherein, The liquid crystal power supply control circuit adjusts the control voltage by means of at least one of digital-to-analog conversion, pulse width modulation and RC discharge.

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