Laser power correction method and system

Abstract

The invention relates to the technical field of laser control, in particular to a laser power correction method and system. The laser power correction method comprises the following steps: acquiring an actual power value corresponding to an actual current value of a laser; fitting based on the actual current value and the actual power value to obtain a fitting broken line; wherein the fitting broken line comprises a plurality of fitting straight lines, and the fitting straight lines correspond to different power intervals of the laser; calculating a proportionality coefficient according to the fitting straight line and a proportionality coefficient calculation formula; according to the proportionality coefficient, a current correction value calculation formula and a power set value of the laser, a current correction value corresponding to the power set value is obtained through calculation, and the current correction value is stored. The current correction value is used as the driving current of the laser, so that the actual output power of the laser is the power set value of the laser, and the accuracy of the laser output power is improved.

Description

Technical Field

[0001] The present invention relates to the field of laser control technology, and in particular to a laser power correction method and system. Background Art

[0002] In recent years, lasers have been widely used in both medical and industrial fields. Generally speaking, laser power is controlled by working current. When the working current of the laser is greater than the initial light output current, that is, the threshold current, the laser starts to output; when the working current of the laser is less than or equal to the threshold current of the laser, the output laser power can be regarded as zero, and there is no laser output; when the laser works at the maximum current, the maximum laser power is output; usually in the range from the threshold current of the laser to the maximum current of the laser, the working current of the laser and the output power of the laser are theoretically linearly proportional. By adjusting the working current, the output power of the laser can be controlled.

[0003] At present, due to changes in ambient temperature or changes in the characteristics of the laser device itself, in the range from the laser threshold current to the laser maximum current, the actual output power of the laser is not strictly linearly proportional to the laser working current, but there is a slight deviation. For industrial fields or large output power, this slight deviation has little effect and can be ignored. However, in the medical field, when the laser is used in low-power medical fields (for example, within 100W), the accuracy requirements for the output laser power are particularly strict. At this time, how to improve the accuracy of the laser output power becomes extremely important. Summary of the invention

[0004] The purpose of the present invention is to provide a laser power calibration method and system to solve the problem of insufficient accuracy of current laser output power.

[0005] An embodiment of the present invention provides a laser power correction method, which is applied to a laser, and the method includes the following steps: obtaining an actual power value corresponding to an actual current value of the laser; wherein the actual current value is measured by a current sampling device, and the actual power value is measured by a standard power meter; performing fitting based on the actual current value and the actual power value to obtain a fitting broken line; wherein the fitting broken line includes multiple fitting straight lines and the fitting straight lines correspond to different power intervals of the laser; according to the fitting straight line and a proportional coefficient calculation formula, a proportional coefficient is calculated; according to the proportional coefficient, a current correction value calculation formula and a power setting value of the laser, a current correction value corresponding to the power setting value is calculated, and the current correction value is stored; wherein the power setting value is the output power of the laser set based on actual needs.

[0006] Optionally, the fitting based on the actual current value and the actual power value to obtain the fitting broken line includes: determining the separation point of the actual laser power variation range of the laser according to the nonlinear characteristics of the discrete points composed of the actual current value and the actual power value; wherein the separation point makes the current-power relationship in the final fitting broken line close to the collected actual current-actual power relationship; dividing the actual laser power variation range according to the power value of the separation point to obtain different power ranges of the laser; and fitting the fitting straight lines corresponding to each power range according to the discrete points in each power range, and the combination of the fitting straight lines constitutes the fitting broken line.

[0007] Optionally, the method also includes: calculating a fitting power value corresponding to the actual current value based on the fitting broken line; judging whether the difference between the fitting power value and the actual power value corresponding to the actual current value exceeds a preset error; if the difference exceeds the preset error, redetermining the separation point to obtain a new fitting straight line until the difference corresponding to the new fitting broken line does not exceed the preset error; if the difference does not exceed the preset error, performing laser power correction based on the fitting broken line, and storing the corresponding current correction value.

[0008] Optionally, the calculating the proportional coefficient according to the fitting straight line and the proportional coefficient calculation formula includes: obtaining the slope and the constant term of the fitting straight line; substituting the slope and the constant term into the proportional coefficient calculation formula to obtain the proportional coefficient corresponding to the fitting straight line, wherein the proportional coefficient includes a first proportional coefficient and a second proportional coefficient; The proportional coefficient calculation formula is as follows: , , in, is the slope of the fitting line, is the constant term of the fitted straight line, is the maximum output power value of the laser, is the threshold current value of the laser, is the maximum current value of the laser, is the first proportionality coefficient, is the second proportional coefficient.

[0009] Optionally, the calculating the current correction value corresponding to the power setting value according to the proportional coefficient, the current correction value calculation formula and the power setting value of the laser comprises: obtaining the proportional coefficient of the power interval corresponding to the fitting straight line by determining the power interval to which the power setting value of the laser belongs; substituting the proportional coefficient and the power setting value of the laser into the current correction value calculation formula to obtain the current correction value corresponding to the power setting value; The current correction value calculation formula is as follows: , in, is the current correction value corresponding to the power setting value, is the power setting value of the laser, is the maximum output power value of the laser, is the threshold current value of the laser, is the maximum current value of the laser, is the first proportionality coefficient, is the second proportional coefficient.

[0010] Optionally, obtaining the actual power value corresponding to the actual current value of the laser includes: controlling a preset current to be input into the laser, and obtaining the actual current value of the laser through a current sampling device; obtaining the actual power value corresponding to the actual current value through a standard power meter; wherein the actual current value of the laser corresponds one-to-one to the actual power value of the laser.

[0011] Optionally, the obtaining of the actual current value of the laser by the current sampling device includes: if the laser works in CW mode, random sampling or sampling in a first preset period to obtain a first sampling result; if the laser works in PWM mode and the pulse frequency of the PWM mode is less than or equal to the preset frequency, sampling in a second preset period to obtain a second sampling result; if the laser works in PWM mode and the pulse frequency of the PWM mode is greater than the preset frequency and the pulse width of the PWM mode is greater than the conversion cycle time of the ADC chip, sampling in a third preset period to obtain a third sampling result; the first sampling result or the second sampling result or the third sampling result is brought into the actual current value calculation formula to obtain the actual current value; wherein the first preset period and the second preset period are non-fixed periods, the third preset period is a fixed period, and the first preset period and the second preset period are both greater than or equal to the third preset period; The actual current value calculation formula is as follows: , , in, is the average sampling current of the ADC chip, is the sampling current value of the ADC chip, is the number of sampling times and , is the maximum sampling current of the ADC chip, is the minimum sampling current of the ADC chip, is the actual current value, is the full data of the ADC chip, It is the maximum current value of the hardware.

[0012] Optionally, the method further includes: when a rising edge of a pulse signal of the PWM mode is detected, starting to synchronously read the sampling current value of the ADC chip; before a falling edge of a pulse signal of the PWM mode is detected, acquiring at least one sampling current value of the ADC chip.

[0013] Optionally, the method further includes: when the deviation between the preset current and the actual current value is greater than a preset difference, and the deviation is greater than the preset difference for a preset number of times, the laser issues a current abnormality alarm and shuts down the laser.

[0014] Compared with the prior art, the laser power correction method provided by the present invention has the following beneficial effects: The laser power correction method provided by the embodiment of the present invention obtains the actual power value corresponding to the actual current value of the laser. Fitting is performed based on the actual current value and the actual power value to obtain a fitting broken line; wherein the fitting broken line includes multiple fitting straight lines and the fitting straight lines correspond to different power intervals of the laser. According to the fitting straight line and the proportional coefficient calculation formula, the proportional coefficient is calculated. According to the proportional coefficient, the current correction value calculation formula and the power setting value of the laser, the current correction value corresponding to the power setting value is calculated and stored. The above-mentioned current correction value is used as the driving current of the laser, so that the actual output power of the laser is the power setting value of the laser, thereby improving the accuracy of its laser output power.

[0015] An embodiment of the present invention provides a laser power correction system for implementing the above-mentioned laser power correction method, the system comprising: an acquisition module, for acquiring an actual power value corresponding to the actual current value of the laser; wherein the actual current value is measured by a current sampling device, and the actual power value is measured by a standard power meter; a fitting module, for performing fitting based on the actual current value and the actual power value to obtain a fitting broken line; wherein the fitting broken line comprises multiple fitting straight lines and the fitting straight lines correspond to different power intervals of the laser; a first calculation module, for calculating a proportional coefficient according to the fitting straight line and a proportional coefficient calculation formula; a second calculation module, for calculating a current correction value corresponding to the power setting value according to the proportional coefficient, a current correction value calculation formula and a power setting value of the laser, and storing the current correction value; wherein the power setting value is the output power of the laser set based on actual needs.

[0016] The laser power calibration system provided by the embodiment of the present invention has the beneficial effect of being able to achieve the same technical effect as the above-mentioned laser power calibration method, which will not be described again here to avoid repetition. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 A schematic flow chart of a laser power calibration method provided in an embodiment of the present invention; Figure 2 A schematic diagram of a standard power-current straight line in an embodiment of the present invention; Figure 3 Schematic diagram of the structure of the laser power correction system in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0020] The embodiment of the present invention provides a laser power calibration method, which is applied to a laser. Figure 1 A schematic flow chart of a laser power calibration method is shown, the method comprising the following steps: S110, obtaining an actual power value corresponding to an actual current value of the laser.

[0021] The actual current value is measured by a current sampling device, and the actual power value is measured by a standard power meter.

[0022] Optionally, the above step S110 includes: controlling a preset current to be input into the laser, obtaining the actual current value of the laser through a current sampling device; and obtaining the actual power value corresponding to the actual current value through a standard power meter. The actual current value of the laser corresponds to the actual power value of the laser one-to-one.

[0023] S120, performing fitting based on the actual current value and the actual power value to obtain a fitting broken line; wherein the fitting broken line includes a plurality of fitting straight lines and the fitting straight lines correspond to different power intervals of the laser.

[0024] Optionally, the above step S120 includes: determining the separation point of the actual laser power variation interval of the laser according to the nonlinear characteristics of the discrete points composed of the above actual current value and the above actual power value; wherein the above separation point makes the current-power relationship in the final fitting broken line close to the actual current-actual power relationship, that is, the error is not greater than 10%. The above actual laser power variation interval is divided according to the power value of the above separation point to obtain different power intervals of the laser; according to the discrete points in each power interval, the fitting straight line corresponding to each power interval is fitted, and the combination of the fitting straight lines constitutes the above fitting broken line.

[0025] S130, calculating the proportionality coefficient according to the above fitting straight line and the proportionality coefficient calculation formula.

[0026] Optionally, the step S130 includes: obtaining the slope and constant term of the fitting straight line; substituting the slope and the constant term into a proportional coefficient calculation formula to obtain a proportional coefficient corresponding to the fitting straight line, the proportional coefficient including a first proportional coefficient and a second proportional coefficient; The proportionality coefficient is calculated as follows: , , in, is the slope of the above fitting line, is the constant term of the above fitting straight line, is the maximum output power of the laser, is the threshold current value of the laser, is the maximum current value of the laser, is the first proportionality coefficient, is the second proportionality coefficient.

[0027] S140, calculating a current correction value corresponding to the power setting value according to the above-mentioned proportionality coefficient, the current correction value calculation formula and the power setting value of the laser, and storing the current correction value.

[0028] The above power setting value is the output power of the laser set based on actual needs.

[0029] Optionally, the step S140 includes: determining the power interval to which the power setting value of the laser belongs, obtaining a proportionality coefficient of the fitted straight line corresponding to the power interval; substituting the proportionality coefficient and the power setting value of the laser into a current correction value calculation formula to obtain a current correction value corresponding to the power setting value; The current correction value calculation formula is as follows: , in, is the current correction value corresponding to the above power setting value, is the power setting value of the laser, is the maximum output power of the laser, is the threshold current of the laser, is the maximum current of the laser, is the first proportionality coefficient, is the second proportionality coefficient.

[0030] Optionally, the method further includes: obtaining a fitting power value corresponding to the actual current value according to the fitting broken line calculation; determining whether the difference between the fitting power value and the actual power value corresponding to the actual current value exceeds a preset error; if the difference exceeds the preset error, redetermining the separation point to obtain a new fitting straight line until the difference corresponding to the new fitting broken line does not exceed the preset error; if the difference does not exceed the preset error, performing laser power correction based on the fitting broken line, and storing the corresponding current correction value.

[0031] Optionally, the above-mentioned obtaining of the actual current value of the laser by the current sampling device includes: if the laser operates in CW mode, random sampling or sampling with a first preset period to obtain a first sampling result; if the laser operates in PWM mode and the pulse frequency of the PWM mode is less than or equal to the preset frequency, sampling with a second preset period to obtain a second sampling result; if the laser operates in PWM mode and the pulse frequency of the PWM mode is greater than the preset frequency and the pulse width of the PWM mode is greater than the conversion cycle time of the ADC chip, sampling with a third preset period to obtain a third sampling result; the above-mentioned first sampling result or the above-mentioned second sampling result or the above-mentioned third sampling result is substituted into the actual current value calculation formula to obtain the actual current value.

[0032] The first preset period and the second preset period are non-fixed periods, the third preset period is a fixed period, and both the first preset period and the second preset period are greater than or equal to the third preset period.

[0033] The actual current value is calculated as follows: , , in, is the average sampling current of the ADC chip, is the sampling current value of the ADC chip, is the number of sampling times and , is the maximum sampling current of the ADC chip, is the minimum sampling current of the ADC chip, is the actual current value, is the full data of the ADC chip, It is the maximum current value of the hardware.

[0034] Exemplarily, when the laser operates in CW mode, the sampling time of the laser current is not restricted, and accurate sampling can be achieved at any time, that is, random sampling can be performed to achieve the required sampling number of times, or sampling can be performed at a preset period to achieve the required sampling number of times. This preset period can be set to a cycle time greater than 100ms to reduce the operating load of the CPU.

[0035] Exemplarily, when the laser is working in PWM mode, the sampling of the laser current has a timing requirement, that is, the sampling moment must be synchronized with the laser PWM pulse, otherwise the sampling value is inaccurate. Specifically, by determining the minimum PWM pulse width of the laser (generally determined by the application requirements of the system) and the single ADC conversion cycle time of the current sampling device (the ADC conversion cycle time is determined by the ADC conversion chip), and ensuring that the minimum laser pulse width time must be greater than the single ADC conversion cycle time of the analog quantity sampling, so that the laser pulse can have enough time to complete the ADC sampling. In addition, within a preset sampling cycle, when the rising edge of the laser PWM pulse signal is detected, the laser current analog quantity signal is synchronously read, and at least one laser current analog quantity ADC sampling is completed before the falling edge of the laser PWM pulse. Further, it can be divided into two cases: the first case, when the pulse frequency of the PMW mode is lower than the preset frequency (for example, 10Hz, that is, the pulse width ≥ 100ms), in this case, the CPU has enough time to complete the analog sampling, and the current analog sampling is performed in the PWM cycle or multiple PWM cycles; the second case, when the pulse frequency of the PWM mode is higher than the preset frequency (for example, 10Hz), the current analog sampling is fixed at a cycle of 100ms to reduce the CPU's operating load. It should be noted that in the above two cases, the minimum laser pulse width time is greater than the single ADC conversion cycle time of analog sampling.

[0036] Optionally, the method further includes: when a rising edge of a pulse signal in a PWM mode is detected, starting to synchronously read an ADC chip sampling current value; before a falling edge of a pulse signal in a PWM mode is detected, acquiring at least one ADC chip sampling current value.

[0037] Optionally, the method further includes: when the deviation between the preset current and the actual current is greater than a preset difference, and the deviation is greater than the preset difference for a preset number of times, the laser issues a current abnormality alarm and shuts down the laser.

[0038] Exemplarily, when it is detected that the deviation between the preset current and the actual current value is greater than the preset difference, and the number of times this situation is detected reaches a preset number, the laser issues a current abnormality alarm and shuts down the laser.

[0039] The laser power correction method provided by the embodiment of the present invention obtains the actual power value corresponding to the actual current value of the laser; wherein the actual current value is measured by a current sampling device, and the actual power value is measured by a standard power meter. Fitting is performed based on the above-mentioned actual current value and the above-mentioned actual power value to obtain a fitting broken line; wherein the fitting broken line includes multiple segments of fitting straight lines and the above-mentioned fitting straight lines correspond to different power intervals of the laser. According to the fitting straight line and the proportional coefficient calculation formula, the proportional coefficient is calculated. According to the above-mentioned proportional coefficient, the current correction value calculation formula and the power setting value of the laser, the current correction value corresponding to the power setting value is calculated and stored; wherein the power setting value is the output power set by the laser based on actual needs. The above-mentioned current correction value is used as the driving current of the laser, so that the actual output power of the laser is the power setting value of the laser, thereby improving the accuracy of its laser output power. In addition, the fitting power value corresponding to the actual current value is calculated based on the fitting line; it is determined whether the difference between the fitting power value and the actual power value corresponding to the actual current value exceeds the preset error; if the difference exceeds the preset error, the separation point is re-determined to obtain a new fitting straight line until the difference corresponding to the new fitting line does not exceed the preset error; if the difference does not exceed the preset error, the laser power is corrected based on the fitting line, and the corresponding current correction value is stored. Thus, the fitting line can accurately reflect the actual power-current relationship, further improving the accuracy of correcting the laser output power.

[0040] The embodiment of the present invention provides a specific laser power calibration method. According to the factory report of the laser diode (LD), in theory, the driving current of the laser diode and the laser output power of the laser diode satisfy a linear equation, that is, the driving current and output power of the laser theoretically satisfy a linear equation; wherein the driving current of the laser is between its threshold current and the maximum current it can withstand.

[0041] See also Figure 2 The standard power-current straight line diagram shown in the figure; is the current, the ordinate is the power. According to the geometric similar triangle determination theorem, the standard formula is as follows: , in, is the theoretical laser drive current setting value, Set the power value for the laser. is the maximum power value of the laser, is the maximum current value of the laser, is the threshold current value of the laser. , , is a fixed value, so and The two satisfy a linear equation of one variable.

[0042] After deformation, the calculation formula of the laser working current is as follows: , Therefore, according to the required power value (ie the power setting value of the above laser), the theoretical value of the laser working current (ie the above theoretical driving current setting value of the laser) is given.

[0043] However, in real application cases, when different lasers are powered by the same drive current, there are differences in the laser power output between different lasers. To eliminate this difference, it is necessary to correct the output power by correcting the laser drive current to achieve the expected output. The essence of this correction of the laser drive current is to modify the theoretical power-current relationship of the laser diode. From the above power-current relationship, it can be seen that by adjusting the standard formula and This changes the slope of the power-current relationship.

[0044] Therefore, based on this, by giving and Multiply each by a proportional coefficient and rewrite the above laser working current calculation formula as follows: , in, is the first proportionality coefficient, is the second proportionality coefficient.

[0045] use replace , replace , after transformation, we get a linear equation: , (1) in, , .

[0046] The software will draw the standard power-current straight line according to the above standard formula, and draw the actual power-current polyline according to the actual collected values; the actual power-current polyline includes multiple fitting straight lines. , The values ​​can be obtained based on the fitted straight line. , In case of value, the proportionality factor and It can be calculated to determine the degree of deviation of the actual power-current relationship compared to the standard power-current relationship, and then according to the above proportionality coefficient and Determine the laser operating current corresponding to the power setting value, that is, calculate the current correction value.

[0047] To distinguish it from the theoretical laser drive current setting value mentioned above, replace , the current correction value calculation formula is as follows: , in, is the current correction value corresponding to the power setting value, is the power setting value of the laser, is the maximum output power of the laser, is the threshold current value of the laser, is the maximum current value of the laser, is the first proportionality coefficient, The above current correction value is the working current of the laser to achieve the output at the power setting value.

[0048] Exemplarily, the embodiment of the present invention provides a feasible segmented fitting method. According to the nonlinear characteristics of the actual power-current relationship of the laser, determine how many regions deviate from the linear region, and correct them in segments according to the number of deviated regions; in each segment, fit a straight line based on discrete points (points determined by the actual current value and the actual power value), and calculate the correction coefficient corresponding to each fitted straight line. and , thereby determining the laser working current correction value corresponding to the power setting value. Specifically, according to the nonlinear characteristics of the discrete points composed of the actual current value and the actual power value, determine the separation point of the actual laser power change interval of the laser; wherein the above separation point makes the current-power relationship in the final fitting broken line close to the actual current-actual power relationship collected; the actual laser power change interval is divided according to the power value of the separation point to obtain different power intervals of the laser; according to the discrete points in each power interval, the fitting straight line corresponding to each power interval is fitted, and the above fitting straight lines are combined to form a fitting broken line. If there are three deviation areas, two separation points need to be determined to divide the actual laser power change interval of the laser into three segments; for example, the power change interval of the laser (assuming the interval is 0~20W) is divided into: (Assume the power value is 0~5W); (Assuming the power value is 5.1~10W); (Assume that the power value is 10.1~20W). In addition, the fitted power value corresponding to the actual current value in each segment is calculated based on the fitting line, and it is further determined whether the difference between the fitted power value in each segment and the actual power value corresponding to the actual current value in each segment is within the preset error range; if so, it means that the final fitted line meets the actual demand, and the power correction is performed based on the above fitting line and the corresponding correction current is stored; if not, the separation point is re-determined to perform segmented fitting to obtain a new fitting line, until the difference corresponding to the new fitting line is within the preset error range.

[0049] For example, the embodiment of the present invention provides another feasible segmented fitting method. The laser power variation interval is divided into n equal parts (n is a positive integer), and a straight line is fitted in each segment according to discrete points (points determined by actual current value and actual power value). The correction coefficient corresponding to each fitted straight line is calculated. and , thereby determining the laser working current correction value corresponding to the power setting value. Specifically, determine n-1 separation points of the actual laser power variation range of the laser; wherein the separation points make the current-power relationship in the final fitting broken line close to the actual current-actual power relationship collected; divide the actual laser power variation range according to the power value of the separation point to obtain different power ranges of the laser; according to the discrete points in each power range, fit the corresponding fitting straight line of each power range, and combine the above fitting straight lines to form a fitting broken line. If the laser power variation range is divided into 4 equal parts, then determine the 3 separation points of the actual laser power variation range of the laser; for example, divide the laser power variation range (assuming the range is 0~20W) into: (Assume the power value is 0~5W); (Assuming the power value is 5.1~10W); (Assuming the power value is 10.1~15W); (Assume that the power value is 15.1~20W). In addition, the fitted power value corresponding to the actual current value in each segment is calculated based on the fitting line, and it is further determined whether the difference between the fitted power value in each segment and the actual power value corresponding to the actual current value in each segment is within the preset error range; if so, it means that the final fitted line meets the actual demand, and the power correction is performed based on the above fitting line and the corresponding correction current is stored; if not, the n value is increased to re-determine the separation point for segmented fitting to obtain a new fitting line, until the difference corresponding to the new fitting line is within the preset error range.

[0050] Optionally, the fitting power value corresponding to the actual current value in each segment is obtained by calculating the fitting line, which can be obtained by taking the actual current as The value of is input into the above formula (1) to calculate value, the The value is the fitted power value corresponding to the actual current value.

[0051] If there is an error between the actual laser output power and the power setting value of the laser, the output power can be corrected by fine-tuning the laser working current, that is, the laser working current is fine-tuned according to the calculation result of the above current correction value calculation formula to achieve corrected output, that is to say, correcting the laser power is achieved by correcting the laser current.

[0052] Multiple linear equations based on the actual collected current-power curves (multiple straight lines) are stored, and each straight line corresponds to a power value in the power change range. When different power values ​​need to be output, the corresponding straight line is automatically called to calculate the current correction value of the laser, and then the current correction value is used as the driving current of the laser to realize the correction of the laser power.

[0053] While calibrating the laser power, current analog sampling is also performed. Current analog sampling usually collects the actual current value of the laser. When the deviation between the set current value (i.e. the preset current mentioned above) and the actual current value is greater than 10% of the actual current value, and the sampled current value is detected to be out of limit for multiple consecutive times (3 or 5 times), the current abnormality alarm is prompted and the laser is turned off.

[0054] Actual current sampling of the laser: Usually there are two modes of laser output, namely CW mode and PWM mode. When the laser works in CW mode, the sampling time is not limited and accurate sampling can be achieved at any time. When the laser works in PWM mode, there are timing requirements for sampling of laser current, that is, the sampling time must be synchronized with the laser PWM pulse, otherwise the sampling value will be inaccurate.

[0055] When the laser works in PWM mode, the specific sampling calculation process is as follows: 1. First, determine the minimum PWM pulse width of the laser (generally determined by the application requirements of the system) and the single ADC conversion cycle time of analog sampling (ADC conversion cycle time is determined by the ADC conversion chip), and ensure that the minimum laser pulse width time must be greater than the single ADC conversion cycle time of analog sampling, so that each laser pulse has enough time to complete ADC sampling. Suppose the laser pulse time is , the ADC conversion time period is , then , ( is the number of sampling times within one laser pulse time, ).

[0056] 2. By detecting the rising edge of the laser PWM pulse signal, start synchronously reading the laser current analog signal, and complete at least one laser current analog ADC sampling before the falling edge of the laser PWM pulse.

[0057] 3. One-time continuous Sample the laser current analog signal 10 times (this project actually samples 10 times continuously), sum it, and then subtract the maximum and minimum values ​​to get the average value; , in, is the average sampling current of the ADC chip, is the sampling current value of the ADC chip, is the number of sampling times and , is the maximum sampling current of the ADC chip, It is the minimum sampling current of the ADC chip.

[0058] 4. Convert the ADC sampling value into the laser sampling current value : , in, is the laser sampling current value. That is, the actual current value mentioned above, is the full data of the ADC chip, It is the maximum current value of the hardware.

[0059] It should be noted that the embodiment of the present invention adopts 16 BIT ADC, and the full amount of data is 65535 ( ); When using 10 BIT and 12 BIT, the full amount of data is 1023 ( )、4095( ), and so on.

[0060] 5. When the PMW frequency is lower than 10Hz, that is, the pulse width is ≥100ms, in this case, the CPU has enough time to complete the analog sampling, and the current analog sampling is performed once in each PWM cycle (continuous When the PWM frequency is higher than 10Hz, the current analog value is sampled and calculated once every 100ms to reduce the CPU operating load.

[0061] The embodiment of the present invention provides a laser power calibration system for implementing the above-mentioned laser power calibration method. Figure 3 The laser power correction system shown in FIG. 1 includes: The acquisition module 310 is used to acquire an actual power value corresponding to an actual current value of the laser.

[0062] The actual current value is measured by a current sampling device, and the actual power value is measured by a standard power meter.

[0063] The fitting module 320 is used to perform fitting based on the actual current value and the actual power value to obtain a fitting broken line; wherein the fitting broken line includes multiple fitting straight lines and the fitting straight lines correspond to different power intervals of the laser.

[0064] The first calculation module 330 is used to calculate the proportionality coefficient according to the above-mentioned fitting straight line and the proportionality coefficient calculation formula.

[0065] The second calculation module 340 is used to calculate the current correction value corresponding to the power setting value according to the above-mentioned proportionality coefficient, the current correction value calculation formula and the power setting value of the laser, and store the current correction value.

[0066] The above power setting value is the output power of the laser set based on actual needs.

[0067] The laser power calibration system provided by the embodiment of the present invention has the beneficial effect of being able to achieve the same technical effect as the above-mentioned laser power calibration method, which will not be described again here to avoid repetition.

[0068] Of course, those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the control device through a computer, and the program can be stored in a computer-readable storage medium. When the program is executed, it may include the processes of the above-mentioned method embodiments, wherein the storage medium may be a memory, a disk, an optical disk, etc.

[0069] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements. The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0070] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A laser power calibration method, characterized in that: Applied to a laser, the method comprises the following steps: Obtaining an actual power value corresponding to an actual current value of the laser; wherein the actual current value is measured by a current sampling device, and the actual power value is measured by a standard power meter; Performing fitting based on the actual current value and the actual power value to obtain a fitting broken line; wherein the fitting broken line includes multiple fitting straight lines and the fitting straight lines correspond to different power intervals of the laser; Calculate the proportionality coefficient according to the fitting straight line and the proportionality coefficient calculation formula; According to the proportional coefficient, the current correction value calculation formula and the power setting value of the laser, the current correction value corresponding to the power setting value is calculated and stored; wherein the power setting value is the output power of the laser set based on actual needs.

2. The laser power calibration method according to claim 1, characterized in that: The performing fitting based on the actual current value and the actual power value to obtain a fitting broken line includes: Determine the separation point of the actual laser power variation interval of the laser according to the nonlinear characteristics of the discrete points formed by the actual current value and the actual power value; wherein the separation point makes the current-power relationship in the final fitting broken line close to the actual current-actual power relationship collected; Dividing the actual laser power variation interval according to the power value of the separation point to obtain different power intervals of the laser; According to the discrete points in each of the power intervals, a fitting straight line corresponding to each of the power intervals is fitted, and the fitting straight lines are combined to form the fitting broken line.

3. The laser power calibration method according to claim 2, characterized in that: The method further comprises: Calculate the fitted power value corresponding to the actual current value according to the fitted broken line; Determine whether a difference between the fitted power value and an actual power value corresponding to the actual current value exceeds a preset error; If the difference exceeds the preset error, the separation point is re-determined to obtain a new fitting straight line until the difference corresponding to the new fitting broken line does not exceed the preset error; if the difference does not exceed the preset error, the laser power is corrected based on the fitting broken line, and the corresponding current correction value is stored.

4. The laser power calibration method according to claim 1, characterized in that: The calculating the proportionality coefficient according to the fitting straight line and the proportionality coefficient calculation formula includes: Obtaining the slope and constant term of the fitted straight line; Substituting the slope and the constant term into a proportional coefficient calculation formula to obtain a proportional coefficient corresponding to the fitting straight line, wherein the proportional coefficient includes a first proportional coefficient and a second proportional coefficient; The proportional coefficient calculation formula is as follows: ， ， in, is the slope of the fitted straight line, is the constant term of the fitted straight line, is the maximum output power value of the laser, is the threshold current value of the laser, is the maximum current value of the laser, is the first proportionality coefficient, is the second proportional coefficient.

5. The laser power calibration method according to claim 4, characterized in that: The step of calculating the current correction value corresponding to the power setting value according to the proportional coefficient, the current correction value calculation formula and the power setting value of the laser comprises: By determining the power interval to which the power setting value of the laser belongs, obtaining a proportional coefficient of the power interval corresponding to the fitting straight line; Substituting the proportional coefficient and the power setting value of the laser into a current correction value calculation formula to obtain a current correction value corresponding to the power setting value; The current correction value calculation formula is as follows: ， in, is the current correction value corresponding to the power setting value, is the power setting value of the laser, is the maximum output power value of the laser, is the threshold current value of the laser, is the maximum current value of the laser, is the first proportionality coefficient, is the second proportional coefficient.

6. The laser power calibration method according to claim 1, characterized in that: The obtaining of the actual power value corresponding to the actual current value of the laser comprises: Controlling a preset current to be input into the laser, and obtaining an actual current value of the laser through a current sampling device; The actual power value corresponding to the actual current value is obtained by a standard power meter; wherein the actual current value of the laser corresponds to the actual power value of the laser one-to-one.

7. The laser power calibration method according to claim 6, characterized in that: The obtaining the actual current value of the laser by a current sampling device comprises: If the laser operates in CW mode, random sampling or sampling at a first preset period is performed to obtain a first sampling result; If the laser operates in a PWM mode and the pulse frequency of the PWM mode is less than or equal to a preset frequency, sampling is performed at a second preset period to obtain a second sampling result; If the laser operates in PWM mode and the pulse frequency of the PWM mode is greater than the preset frequency and the pulse width of the PWM mode is greater than the conversion cycle time of the ADC chip, sampling is performed at a third preset cycle to obtain a third sampling result; Substituting the first sampling result, the second sampling result, or the third sampling result into an actual current value calculation formula to obtain the actual current value; Wherein, the first preset period and the second preset period are non-fixed periods, the third preset period is a fixed period, and the first preset period and the second preset period are both greater than or equal to the third preset period; The actual current value calculation formula is as follows: ， ， in, is the average sampling current of the ADC chip, is the sampling current value of the ADC chip, is the number of sampling times and , is the maximum sampling current of the ADC chip, is the minimum sampling current of the ADC chip, is the actual current value, is the full data of the ADC chip, It is the maximum current value of the hardware.

8. The laser power calibration method according to claim 7, characterized in that: The method further comprises: When the rising edge of the pulse signal of the PWM mode is detected, the sampling current value of the ADC chip is synchronously read; Before the falling edge of the pulse signal of the PWM mode is detected, at least one sampling current value of the ADC chip is obtained.

9. The laser power calibration method according to claim 6, characterized in that: The method further comprises: When the deviation between the preset current and the actual current value is greater than a preset difference, and the situation where the deviation is greater than the preset difference is detected for a preset number of times, the laser issues a current abnormality alarm and shuts down the laser.

10. A laser power calibration system, characterized in that: For implementing the laser power correction method according to any one of claims 1 to 9, the system comprises: An acquisition module, used for acquiring an actual power value corresponding to an actual current value of the laser; wherein the actual current value is measured by a current sampling device, and the actual power value is measured by a standard power meter; A fitting module, used for performing fitting based on the actual current value and the actual power value to obtain a fitting broken line; wherein the fitting broken line includes multiple fitting straight lines and the fitting straight lines correspond to different power intervals of the laser; A first calculation module, used to calculate the proportionality coefficient according to the fitting straight line and the proportionality coefficient calculation formula; The second calculation module is used to calculate the current correction value corresponding to the power setting value according to the proportional coefficient, the current correction value calculation formula and the power setting value of the laser, and store the current correction value; wherein the power setting value is the output power of the laser set based on actual needs.

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