Temperature control furnace structure and control method

Abstract

The invention provides a temperature control furnace structure and a control method. The temperature control furnace structure comprises a shell, the interior of the shell is hollow, the two sides of the shell protrude outwards, and a plurality of heat insulation pieces are arranged in the shell; the crystal seat is arranged on the plurality of heat insulation pieces, and a groove with two through ends is formed in one side of the crystal seat; a groove is formed in the shell, the frequency doubling crystal is arranged in the groove, transmission holes penetrating into the shell are formed in the protrusions on the two sides of the shell, window pieces are arranged in the transmission holes, and the pressing mechanism is arranged on the side, away from the heat insulation piece, of the crystal holder; the heating piece is arranged on one side of the crystal holder close to the heat insulation piece; the structure ensures the stability of the working temperature of the frequency doubling crystal, a target model of the relationship between the frequency doubling power and the working temperature is constructed by collecting real-time frequency doubling power data at different working temperatures, and the working temperature enabling the frequency doubling power to reach the optimal is found through a genetic algorithm based on the target model, so that the working temperature of the frequency doubling crystal is optimized. And the working stability and reliability of the temperature control furnace are ensured under the condition that the external conditions are severe or changed.

Description

Technical Field

[0001] The invention relates to the technical field of green light frequency doubling laser technology, and in particular to a temperature control furnace structure and a control method. Background Art

[0002] With the continuous development of laser technology, green lasers have shown broad application potential in many fields, such as biomedicine, display technology, industrial processing, etc.; laser frequency doubling technology uses the secondary nonlinear effect of nonlinear crystals under the action of strong lasers to convert the fundamental frequency light with a frequency of ω into the doubled frequency light with a frequency of 2ω after passing through the crystal. At present, the key to achieving high conversion efficiency of green light frequency doubling is to achieve phase matching; angle phase matching uses the birefringence characteristics of crystals to compensate for normal dispersion, thereby achieving phase matching. Compared with angle phase matching technology, non-critical phase matching technology is widely used in the field of green light frequency doubling because there is no phase mismatch problem caused by spatial walk-off effect.

[0003] The temperature control device with the publication number CN220233716U comprises a first heat conducting mechanism, a second heat conducting mechanism, a third heat conducting mechanism, a frequency doubling crystal, a temperature detector, a heating rod, a base and a cover. The base and the cover together form a heat preservation space, and the first heat conducting mechanism, the second heat conducting mechanism, the third heat conducting mechanism, the frequency doubling crystal and the heating rod are all located in the heat preservation space; the first heat conducting mechanism is L-shaped, comprising a left structure and a lower structure, and the frequency doubling crystal is arranged at the corner of the L-shape of the first heat conducting mechanism, that is, the first heat conducting mechanism is directly close to the left surface and the lower surface of the frequency doubling crystal; the second heat conducting mechanism is directly close to the upper surface of the frequency doubling crystal; the third heat conducting mechanism is directly close to the right surface of the frequency doubling crystal, and the four sides of the frequency doubling crystal are heated by the first heat conducting mechanism, the second heat conducting mechanism and the third heat conducting mechanism, so that the frequency doubling crystal is stably in the frequency doubling temperature environment.

[0004] The non-critical phase matching technology used in the above-mentioned existing schemes is based on the temperature-sensitive characteristics of the refractive index of the frequency doubling crystal. Therefore, the offset of the crystal position, the control accuracy of the temperature control system, and the temperature gradient distribution inside the frequency doubling crystal caused by the increase of the fundamental frequency light power will affect the optimal operating temperature of the frequency doubling crystal, thereby affecting the final frequency doubling result and stability. Summary of the invention

[0005] In view of this, the present invention proposes a temperature control furnace structure and control method, which can ensure the stability of the working environment temperature of the frequency doubling crystal and accurately control the frequency doubling crystal at an optimal working temperature, thereby improving its performance and stability.

[0006] The technical solution of the present invention is implemented as follows: In the first aspect, the present invention provides a temperature control furnace structure, including a shell, a plurality of heat insulation components, a crystal seat, a frequency doubling crystal, a clamping mechanism, a heating component and a temperature detection component, wherein:

[0007] The interior of the shell is hollow, and the two sides are convex outwards;

[0008] A plurality of heat insulating components are arranged in the shell and are arranged at intervals;

[0009] The crystal seat is arranged on a plurality of heat insulating members, and the crystal seat is spaced apart from the inner wall of the shell, and a groove with two ends passing through is opened on one side of the crystal seat;

[0010] The frequency doubling crystal is arranged in the groove, and the projections on both sides of the shell are provided with transmission holes penetrating to the interior, and the positions of the transmission holes on both sides correspond to the positions of the two ends of the groove respectively, for the external laser to be incident and emitted;

[0011] A window piece is arranged in the transmission hole to prevent dust and heat from entering the shell.

[0012] The clamping mechanism is arranged on a side of the crystal seat away from the heat insulating member, and is used to longitudinally fix the frequency doubling crystal in the groove;

[0013] The heating element is arranged on one side of the crystal seat close to the heat insulating element and is located at the center, and is used to uniformly heat the frequency doubling crystal;

[0014] The temperature detection component is arranged on one side of the crystal seat and is used to monitor the temperature of the frequency doubling crystal.

[0015] Based on the above technical solution, preferably, the outer side of the frequency doubling crystal is wrapped with a tin-indium alloy film, which is used to fix the frequency doubling crystal to the crystal seat by hot melting, and the size of the frequency doubling crystal matches that of the groove, and the frequency doubling crystal is tightly fixed in the groove.

[0016] On the basis of the above technical solution, preferably, the housing includes a backing plate and an outer shell, wherein:

[0017] The shell is fixed on the backing plate by bolts, and the shell is a stainless steel insulation shell;

[0018] The plurality of heat insulating components are all fixed on the backing plate and are all located in the outer shell. The material of the heat insulating components is glass.

[0019] On the basis of the above technical solution, preferably, the clamping mechanism comprises a pressure cover, an upper cover, a plurality of first elastic members, a plurality of second elastic members and a pressure block, wherein:

[0020] The pressure cover is arranged on a side of the crystal seat away from the thermal insulation member;

[0021] The plurality of first elastic members are arranged on one side of the pressure cover close to the crystal seat and are arranged at even intervals, and the other side of the plurality of first elastic members extends into the groove;

[0022] The pressing block is fixed between the first elastic members and one side away from the pressing cover, the pressing block is located in the groove and abuts against the frequency doubling crystal;

[0023] The upper cover is fixed to a side of the pressure cover away from the first elastic member;

[0024] The plurality of second elastic members are all arranged on one side of the upper cover away from the crystal seat and are arranged at even intervals. The other sides of the plurality of second elastic members are all in contact with the inner wall of the outer shell.

[0025] On the basis of the above technical solution, preferably, it also includes a mounting seat, a PCB adapter plate and a plurality of terminals, wherein:

[0026] The PCB adapter plate is arranged on the mounting seat;

[0027] The pad is abutted against the side of the PCB adapter plate away from the mounting seat, the housing is fixed to the mounting seat by bolts penetrating the pad and the PCB adapter plate, and an avoidance hole corresponding to the position of the terminal is opened on the pad;

[0028] The plurality of connecting posts are arranged on a side of the PCB adapter plate away from the mounting seat and are electrically connected to the PCB adapter plate. The plurality of connecting posts respectively penetrate corresponding avoidance holes and are electrically connected to the heating element and the temperature detection element.

[0029] On the basis of the above technical solution, preferably, a mounting groove is opened in the middle of the side of the crystal seat, the temperature detection component is arranged in the mounting groove and is adjacent to the frequency doubling crystal, a fixing component is fixed in the mounting groove by bolts, and the temperature detection component is fixed in the mounting groove by bolts through the fixing component.

[0030] In a second aspect, the present invention further provides a method for controlling a temperature-controlled furnace structure, which is implemented using the temperature-controlled furnace structure as described above, and comprises the following steps:

[0031] S1, collecting the optical signal output by the temperature-controlled furnace to the power collection module, so that the power collection module obtains real-time frequency-multiplied power data at different working temperatures corresponding to the output optical signal;

[0032] S2, constructing an initial model based on the collected real-time frequency-multiplied power data at different operating temperatures, and determining the parameters of the target model by the least square method to obtain the target model;

[0033] S3, using genetic algorithm to optimize the target model, solving for the optimal working temperature, and controlling the working temperature of the temperature control furnace according to the optimal working temperature.

[0034] On the basis of the above technical scheme, preferably, in step S1, real-time frequency doubling power data under different working temperatures are collected, the real-time temperature data of the frequency doubling crystal and the real-time power data of the optical signal output by the frequency doubling crystal are collected through the temperature detection device and the power collection module, the collection time step is preset, the real-time temperature data and the real-time power data are collected according to the time step, and the real-time temperature data and the real-time power data are matched one by one.

[0035] On the basis of the above technical solution, preferably, step S2 includes the following sub-steps:

[0036] S21, based on the real-time frequency-multiplied power data collected at different operating temperatures, construct an initial model, the expression is:

[0037]

[0038] In the formula, θ 0 ,θ 1 ,...,θ n is the constant parameter to be solved, x is the temperature variable, y is the power variable;

[0039] S22, given the initial value of the constant parameter to be solved, defined as θ 0 (0) ,θ 1 (0) ,...,θ n (0) ;

[0040] S23, construct the residual sum of squares function, the expression is as follows:

[0041]

[0042] Where S(θ) is the residual sum of squares, y i is the frequency-multiplied power data at the i-th operating temperature;

[0043] S24, find the gradient of the residual sum of squares with respect to θ, the expression is:

[0044]

[0045] In the formula, θ j is the jth constant parameter to be solved, j = 1, 2, ..., n, is the initial model f with respect to the parameter θ j The partial derivative of i The value at

[0046] S25, iterate the initial model and update the constant parameters to be solved until convergence stops, determine the parameters of the target model, obtain the target model, and update the expression as follows:

[0047]

[0048] In the formula, θ (k) is the parameter value at the kth iteration, and α is the learning rate.

[0049] On the basis of the above technical solution, preferably, step S3 includes the following sub-steps:

[0050] S31, using binary coding to encode the working temperature as individuals in the genetic algorithm;

[0051] S32, randomly generate a group of initial populations, each individual represents a working temperature, set the size of the population to N, and set the range of the working temperature to [T min , T max ], a randomly generated set of initial populations is defined as P 0 ={T 1 , T 2 , ..., T N};

[0052] S33, using the target model to evaluate the fitness of each operating temperature in the initial population, is expressed as:

[0053] F(T)=f(T)

[0054] In the formula, F(T) is the fitness of the working temperature, and f(T) is the fitness function;

[0055] S34, using the roulette wheel selection method, determines the probability of being selected according to the fitness value of the individual, and the expression is:

[0056]

[0057] In the formula, p(m) is the probability of the mth individual being selected;

[0058] S35, pair the selected individuals in pairs, and perform crossover operation on the paired individuals to generate new individuals. The expression is:

[0059] T′ m =βT m +(1-β)T q

[0060] T′ q =βT q +(1-β)T m

[0061] In the formula, β is the crossover rate, and its value range is between 0 and 1;

[0062] S36, random changes are made to each newly generated individual, and the expression is:

[0063] T″ m =T′ m +δ

[0064] In the formula, δ is a random number used to ensure T″ m In [T min ,T max ] within the scope;

[0065] S37, using the newly generated individuals after crossover and mutation to replace the original individuals in the old population to form a new population;

[0066] S38, repeating steps S33 to S37 for iteration until the fitness value reaches convergence and stops, decoding the binary representation of the optimal individual into the working temperature, and obtaining the optimal working temperature.

[0067] The temperature control furnace structure and control method of the present invention have the following beneficial effects compared with the prior art:

[0068] (1) The heat exchange is effectively isolated by the shell, the crystal seat and the shell are spaced apart to reduce heat conduction, the heating element is set at the center of the bottom of the crystal seat for uniform heating, and an NTC with a temperature control accuracy of ±0.01°C is used in conjunction with a clamping mechanism to stably fix the frequency doubling crystal, thereby ensuring the stability of the working environment temperature of the frequency doubling crystal and improving the stability and robustness of the frequency doubling system;

[0069] (2) Wrap the frequency doubling crystal with a tin-indium alloy film and place it in the center of the groove. The hot-melt fixation of the tin-indium alloy film makes the frequency doubling crystal and the groove in close contact, which can significantly improve the stability of the frequency doubling crystal during operation. After melting, the excess tin-indium alloy flows outward from the grooves on both sides of the crystal seat to avoid contaminating the end face of the frequency doubling crystal. In addition, heat can be quickly transferred to the frequency doubling crystal through the tin-indium alloy film to achieve uniform heating of the frequency doubling crystal, ensuring that the frequency doubling crystal maintains a stable temperature during operation and improves its frequency doubling efficiency.

[0070] (3) Through the uniform pressure exerted by the first elastic member on the frequency doubling crystal and the fixing effect of the second elastic member on the pressure cover and the inner wall of the housing, the clamping mechanism can improve the fixing stability of the frequency doubling crystal and prevent the frequency doubling crystal from being broken due to uneven force;

[0071] (4) By collecting data, building models and optimizing parameters, the optimal operating temperature of the temperature-controlled furnace can be automatically found, ensuring the stability and reliability of the temperature-controlled furnace when external conditions are harsh or changing. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] 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 some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0073] Figure 1 It is a three-dimensional diagram of the temperature control furnace structure of the present invention;

[0074] Figure 2 A three-dimensional view of a shell of a temperature-controlled furnace structure of the present invention;

[0075] Figure 3 It is a side view of the temperature control furnace structure of the present invention;

[0076] Figure 4 The temperature control furnace structure of the present invention Figure 3 Sectional view at AA;

[0077] Figure 5 A three-dimensional diagram of a crystal seat of a temperature-controlled furnace structure of the present invention;

[0078] Figure 6 It is a schematic diagram of the structure of the green light frequency doubling system of the temperature control furnace structure of the present invention;

[0079] Figure 7 It is a flow chart of the control method of the temperature control furnace of the present invention;

[0080] Figure 8 This is a flow chart of step S2 of the temperature control furnace control method of the present invention;

[0081] Fig. 9 It is a flow chart of step S3 of the control method of the temperature control furnace of the present invention;

[0082] Fig.10 It is a least square fitting curve diagram of the control method of the temperature control furnace of the present invention;

[0083] Fig.11 It is the genetic algorithm convergence curve of the temperature control furnace control method of the present invention. DETAILED DESCRIPTION

[0084] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0085] like Figure 1-5 As shown, in the first aspect, the present invention provides a temperature control furnace structure, including a shell 1, a plurality of heat insulating members 2, a crystal seat 3, a frequency doubling crystal 4, a clamping mechanism 5, a heating member 6 and a temperature detecting member 7, wherein the shell 1 is hollow inside and bulges outward on both sides; the plurality of heat insulating members 2 are arranged in the shell 1 and are arranged at intervals; the crystal seat 3 is arranged on the plurality of heat insulating members 2, and the crystal seat 3 is arranged at intervals from the inner wall of the shell 1, and a groove 300 with two ends passing through is opened on one side of the crystal seat 3; the frequency doubling crystal 4 is arranged in the groove 300, and the bulges on both sides of the shell 1 are opened to penetrate to the inside The transmission holes 110 are arranged on both sides, and the positions of the transmission holes 110 on both sides correspond to the positions of the two ends of the groove 300 respectively, for external laser incidence and emission; a window piece 12 is arranged in the transmission hole 110, which plays a role in dust and heat insulation in the shell 1; the clamping mechanism 5 is arranged on the side of the crystal seat 3 away from the insulation member 2, and is used to longitudinally fix the frequency doubling crystal in the groove 300; the heating element 6 is arranged on the side of the crystal seat 3 close to the insulation member 2, and is located at the center, and is used to uniformly heat the frequency doubling crystal 4; the temperature detection element 7 is arranged on one side of the crystal seat 3, and is used to monitor the temperature of the frequency doubling crystal 4.

[0086] It should be noted that the outer shell 102 in this embodiment is a stainless steel insulation shell, which effectively reduces the heat exchange between the inside of the shell 1 and the external environment, and the crystal seat 3 is spaced apart from the inner wall of the shell 1, which further reduces heat conduction and ensures that the working environment temperature of the frequency doubling crystal 4 is relatively stable. The heating element 6 is arranged on the side of the crystal seat 3 close to the insulation element 2 and is located in the center to uniformly heat the frequency doubling crystal 4. The clamping mechanism 5 fixes the frequency doubling crystal 4 longitudinally to prevent the frequency doubling crystal from being broken due to uneven force while fixing it, thereby ensuring that the position of the frequency doubling crystal does not shift and affect the frequency doubling efficiency.

[0087] The centers of both sides of the shell 1 are bulged outward, and the bulged parts are cylindrical, so that the laser power density at the window piece 12 is lower, and the probability of damage to the window piece 12 is lower, thereby effectively improving the service life of the overall structure.

[0088] By arranging window pieces 12 in the transmission holes 110 on both sides, dust can be prevented from entering the housing 1 in the working state and adhering to the light-transmitting surface of the crystal to cause damage to the crystal, thereby effectively improving the service life; and the arranged window pieces 12 do not affect the incident and emitted lasers, thereby avoiding the heat convection phenomenon caused by the exchange of hot and cold air inside and outside the housing, making the working environment temperature of the frequency doubling crystal more stable, shortening the frequency doubling power stabilization time, and improving the stability of the frequency doubling power.

[0089] The outer side of the frequency doubling crystal 4 in this embodiment is wrapped with a tin-indium alloy film, which is used to fix the frequency doubling crystal 4 to the crystal seat 3 by hot melting, and the size of the frequency doubling crystal 4 matches that of the groove 300, and the frequency doubling crystal 4 is tightly fixed in the groove 300.

[0090] It should be noted that the frequency doubling crystal 4 is wrapped with a tin-indium alloy film and placed centrally on the concave crystal seat 3, that is, in the groove 300. The difference in melting points between the tin-indium alloy film, the frequency doubling crystal 4 and the structural parts is used to effectively fix the frequency doubling crystal 4 and the crystal seat 3 together. The thermal melting fixation of the tin-indium alloy film and the close contact between the frequency doubling crystal 4 and the groove 300 can significantly improve the stability of the frequency doubling crystal 4 during operation. After melting, excess tin-indium alloy flows outward from the grooves 300 on both sides of the crystal seat 3 to avoid contaminating the end faces of the frequency doubling crystal 4. As a metal alloy, tin-indium alloy has good thermal conductivity. When the heating element 6 heats the crystal seat 3, heat can be quickly transferred to the frequency doubling crystal 4 through the tin-indium alloy film to achieve uniform heating of the frequency doubling crystal 4. This helps to ensure that the frequency doubling crystal maintains a stable temperature during operation, thereby maintaining a high frequency doubling efficiency working state and achieving good power stability.

[0091] Specifically, the crystal seat 3 in this embodiment is an integrated copper-gold-plated structural part. Copper is a material with high electrical conductivity and high thermal conductivity. The high thermal conductivity of copper helps to ensure that heat can be quickly and evenly transferred to the frequency doubling crystal 4, thereby achieving precise temperature control thereof. The gold-plated layer can provide good antioxidant and corrosion resistance, help protect the copper substrate from erosion by environmental factors, and extend the service life of the crystal seat, thereby ensuring that the frequency doubling crystal 4 can work stably and efficiently for a long time in the temperature-controlled furnace structure.

[0092] The shell 1 in this embodiment includes a pad 101 and an outer shell 102, wherein the outer shell 102 is fixed to the pad 101 by bolts; the plurality of thermal insulation components 2 are all fixed to the pad 101 and are all located in the outer shell 102, and the thermal insulation components 2 are made of glass.

[0093] It should be noted that the pad 101 is made of stainless steel, the outer shell 102 is a stainless steel insulation shell, and the pad 101 and the outer shell 102 form a shell 1 to separate the interior from the outside, effectively reducing the heat exchange between the temperature control furnace and the external environment, and the crystal seat 3 is installed in the shell 1 through the insulation 2, which can further effectively isolate the heat exchange between the inside of the shell and the external environment. The insulation 2 is made of glass. The glass material is not only resistant to high temperatures, but also can prevent heat conduction and convection, thereby improving the insulation effect of the temperature control furnace.

[0094] Furthermore, the heat insulating member 2 has a cylindrical shape, which can stably support the crystal seat 3 while reducing the contact area with the crystal seat 3 and reducing heat exchange.

[0095] The clamping mechanism 5 in this embodiment includes a pressure cover 51, an upper cover 52, a plurality of first elastic members 53, a plurality of second elastic members 54 and a pressure block 55, wherein the pressure cover 51 is arranged on the side of the crystal seat 3 away from the thermal insulation member 2; the plurality of first elastic members 53 are all arranged on the side of the pressure cover 51 close to the crystal seat 3, and are arranged at uniform intervals, and the other sides of the plurality of first elastic members 53 extend into the groove 300; the pressure block 55 is fixed between the sides of the plurality of first elastic members 53 away from the pressure cover 51, the pressure block 55 is located in the groove 300, and abuts against the frequency doubling crystal 4; the upper cover 52 is fixed on the side of the pressure cover 51 away from the first elastic member 53; the plurality of second elastic members 54 are all arranged on the side of the upper cover 52 away from the crystal seat 3, and are arranged at uniform intervals, and the other sides of the plurality of second elastic members 54 abut against the inner wall of the outer shell 102.

[0096] It should be noted that, through the uniform pressure applied by the first elastic member 53 to the frequency doubling crystal 4 and the fixing effect of the second elastic member 54 on the pressure cover 51 and the inner wall of the shell 102, the clamping mechanism 5 can improve the fixing stability of the frequency doubling crystal and avoid the frequency doubling crystal 4 from breaking due to uneven force.

[0097] Specifically, the material of the upper cover 52 in this embodiment is polyimide, and the material of the pressure cover 51 and the pressure block 55 is gold-plated copper.

[0098] The present embodiment also includes a mounting seat 8, a PCB adapter plate 9 and a plurality of terminals 10, wherein the PCB adapter plate 9 is arranged on the mounting seat 8; a pad 101 abuts against the side of the PCB adapter plate 9 away from the mounting seat 8, the housing 102 is fixed to the mounting seat 8 by bolts penetrating the pad 101 and the PCB adapter plate 9, and a avoidance hole 100 corresponding to the position of the terminal 10 is opened on the pad 101; the plurality of terminals 10 are all arranged on the side of the PCB adapter plate 9 away from the mounting seat 8, and are electrically connected to the PCB adapter plate 9, and the plurality of terminals 10 respectively penetrate the corresponding avoidance holes 100 to be electrically connected to the heating element 6 and the temperature detection element 7.

[0099] It should be noted that the mounting base 8 is used to fix and support the shell 1, and the terminal 10 arranged on the PCB adapter plate 9 passes through the pad 101 and extends into the shell 1 to be electrically connected to the heater 6, so as to control the heater 6 to heat the crystal seat 3.

[0100] In this embodiment, a mounting groove is provided in the middle of the side of the crystal seat 3, and the temperature detection component 7 is arranged in the mounting groove and is adjacent to the frequency doubling crystal 4. A fixing component 11 is fixed in the mounting groove by bolts, and the temperature detection component 7 is fixed in the mounting groove by bolts through the fixing component 11.

[0101] It should be noted that by placing the temperature detection component 7 in the mounting groove and adjacent to the frequency doubling crystal 4, it can be ensured that the measured temperature is closer to the actual operating temperature of the frequency doubling crystal 4. The temperature detection component 7 is an NTC thermistor with an accuracy of ±0.01°C, which can accurately monitor the temperature of the frequency doubling crystal. The accurate temperature measurement provides a reliable input signal for the microcontroller. By working in conjunction with the heating component 6, the temperature control system can adjust the heating power in real time according to the measured temperature, thereby achieving precise control of the temperature of the frequency doubling crystal and ensuring that the frequency doubling crystal 4 performs the frequency doubling operation at a stable operating temperature.

[0102] Since the non-critical phase matching technology is based on the temperature-sensitive characteristics of the refractive index of the frequency doubling crystal, the offset of the crystal position, the control accuracy of the temperature control system, and the temperature gradient distribution inside the frequency doubling crystal caused by the increase of the fundamental frequency light power will all affect the optimal operating temperature of the frequency doubling crystal, thereby affecting the final frequency doubling result and stability.

[0103] Therefore, if Figure 7-11 As shown, the present invention provides a control method for a temperature-controlled furnace structure, which is used to ensure that the temperature-controlled furnace always works at an optimal temperature, and is implemented using the temperature-controlled furnace structure as described above, and includes the following steps:

[0104] S1, collecting the optical signal output by the temperature-controlled furnace to the power collection module, so that the power collection module obtains real-time frequency-multiplied power data at different working temperatures corresponding to the output optical signal;

[0105] Among them, in step S1, real-time frequency doubling power data under different working temperatures are collected, and the real-time temperature data of the frequency doubling crystal 4 and the real-time power data of the optical signal output by the frequency doubling crystal 4 are collected through the temperature detection component 7 and the power collection module. The collection time step is preset, and the real-time temperature data and real-time power data are collected according to the time step, and the real-time temperature data and the real-time power data are matched one by one.

[0106] It should be noted that the real-time power data of the optical signal output by the frequency doubling crystal 4 and the corresponding real-time temperature data are obtained at different operating temperatures of the temperature-controlled furnace. The temperature detection element 7 is a high-precision NTC thermistor that can output an electrical signal corresponding to the temperature in real time. The power acquisition module receives and measures the power of the optical signal output by the frequency doubling crystal 4. The module includes a photodetector and a power meter. The photodetector is used to convert the optical signal into an electrical signal. The power meter is used to measure the power of the electrical signal. The real-time temperature data and the real-time power data are collected according to a preset time step, and the real-time temperature data and the real-time power data are matched one by one to form a data set for subsequent model construction and optimization.

[0107] S2, constructing an initial model based on the collected real-time frequency-multiplied power data at different operating temperatures, and determining the parameters of the target model by the least square method to obtain the target model;

[0108] Wherein, step S2 includes the following sub-steps:

[0109] S21, based on the real-time frequency-multiplied power data collected at different operating temperatures, construct an initial model, the expression is:

[0110]

[0111] In the formula, θ 0 ,θ 1 ,...,θ n is the constant parameter to be solved, x is the temperature variable, y is the power variable;

[0112] S22, given the initial value of the constant parameter to be solved, defined as θ 0 (0) ,θ 1 (0) ,...,θ n (0) ;

[0113] S23, construct the residual sum of squares function, the expression is as follows:

[0114]

[0115] Where S(θ) is the residual sum of squares, y i is the frequency-multiplied power data at the i-th operating temperature;

[0116] S24, find the gradient of the residual sum of squares with respect to θ, the expression is:

[0117]

[0118] In the formula, θ j is the jth constant parameter to be solved j=1,2,…,n, is the initial model f with respect to parameter θ j The partial derivative of i The value at

[0119] S25, iterate the initial model and update the constant parameters to be solved until convergence stops, determine the parameters of the target model, obtain the target model, and update the expression as follows:

[0120]

[0121] In the formula, θ (k) is the parameter value at the kth iteration, and α is the learning rate.

[0122] It should be noted that the initial model is constructed, which describes the relationship between the double frequency power and temperature and contains some constant parameters to be solved. In order to find the optimal values ​​of these parameters so that the model can accurately predict the actual data, a residual sum of squares function is constructed. This function measures the difference between the model prediction value and the actual data. The gradient of this function with respect to the parameters is calculated, and the gradient descent method is used to iteratively update the parameters until they converge to a certain stable value. In this process, the continuous updating of the parameters makes the residual sum of squares gradually decrease until it reaches the minimum. Then, the model parameters are solved by the least squares method to obtain a more accurate model. This model can more accurately describe the relationship between the double frequency power and temperature, which helps to improve the accuracy of subsequent prediction and control.

[0123] S3, optimizing the target model using a genetic algorithm to obtain an optimal working temperature, and controlling the working temperature of the temperature control furnace according to the optimal working temperature;

[0124] Wherein, step S3 includes the following sub-steps:

[0125] S31, using binary coding to encode the working temperature as individuals in the genetic algorithm;

[0126] S32, randomly generate a group of initial populations, each individual represents a working temperature, set the size of the population to N, and set the range of the working temperature to [T min ,T max ], a randomly generated set of initial populations is defined as P 0 ={T 1 ,T 2 ,...,T N};

[0127] S33, using the target model to evaluate the fitness of each operating temperature in the initial population, is expressed as:

[0128] F(T)=f(T)

[0129] In the formula, F(T) is the fitness of the working temperature, and f(T) is the fitness function;

[0130] S34, using the roulette wheel selection method, determines the probability of being selected according to the fitness value of the individual, and the expression is:

[0131]

[0132] In the formula, p(m) is the probability of the mth individual being selected;

[0133] S35, pair the selected individuals in pairs, and perform crossover operation on the paired individuals to generate new individuals. The expression is:

[0134] T′ m =βT m +(1-β)T q

[0135] T′ q =βT q +(1-β)T m

[0136] In the formula, β is the crossover rate, and its value range is between 0 and 1;

[0137] S36, random changes are made to each newly generated individual, and the expression is:

[0138] T″ m =T′ m +δ

[0139] In the formula, δ is a random number used to ensure T″ m In [T min , T max ] within the scope;

[0140] S37, using the newly generated individuals after crossover and mutation to replace the original individuals in the old population to form a new population;

[0141] S38, repeating steps S33 to S37 for iteration until the fitness value reaches convergence and stops, decoding the binary representation of the optimal individual into the working temperature, and obtaining the optimal working temperature.

[0142] It should be noted that the target model is optimized by using a genetic algorithm to solve for the optimal working temperature, and the working temperature of the temperature-controlled furnace is controlled according to the optimal working temperature, thereby improving its performance and stability.

[0143] This embodiment collects optical signals output by the temperature-controlled furnace at different operating temperatures and obtains corresponding frequency doubling power data. According to the collected real-time frequency doubling power data at different operating temperatures, a mathematical model capable of describing the relationship between the frequency doubling power and the operating temperature, namely, a target model, is constructed. On the basis of the target model, a genetic algorithm is used to find the operating temperature that makes the frequency doubling power reach the optimal level. The control method of the temperature-controlled furnace structure realizes precise control of the operating temperature of the temperature-controlled furnace by collecting data, constructing models and optimizing parameters, which not only improves the frequency doubling efficiency of the frequency doubling crystal, but also enhances the stability and reliability of the temperature-controlled furnace.

[0144] The above temperature control furnace structure and control method are as follows Figure 6As shown, it is specifically applied in a green light frequency doubling system, which includes a fiber collimator, a half-wave plate, a focusing lens, a temperature-controlled furnace, a collimating lens, a dichroic mirror, a beam expander, a light collecting barrel, a spectroscope, a power collection module and a microcontroller. The principle is that the fiber collimator collimates the divergent fundamental frequency light, and the collimated fundamental frequency light passes through the half-wave plate and the focusing lens in turn. The half-wave plate is used to adjust the polarization state of the fundamental frequency light, and the focusing lens is used to focus the fundamental frequency light. The focused fundamental frequency light passes through the transmission hole 110 and is incident on the frequency doubling crystal 4 in the temperature-controlled furnace. After the crystal is frequency doubling, the generated frequency doubling light and the residual fundamental frequency light are emitted from the transmission hole 110 on the other side. The temperature-controlled furnace is used to fix the frequency doubling crystal and maintain the working temperature of the frequency doubling crystal. The emitted laser passes through the collimating lens and the dichroic mirror in turn. The collimating lens is used to collimate the frequency doubling light. The dichroic mirror has high transmittance to the fundamental frequency light and high reflectance to the frequency doubling light, and is used to separate the residual fundamental frequency light and the frequency doubling light. The frequency light is collected into the light collecting barrel through the beam expander. The beam expander is used to increase the size of the base frequency light spot to prevent the laser power density at the light collecting barrel from being too high and damaging the structural parts or causing overheating of the structural parts. The light collecting barrel is used to collect the residual base frequency light that has not been frequency doubled. The frequency doubled light is reflected by the beam splitter for subsequent applications. The beam splitter is used to separate a small amount of frequency doubled light into the power collection module for power monitoring. In addition, the dichroic mirror and the beam splitter are also used to adjust the beam directivity of the output frequency doubled light, and transmit the temperature of the frequency doubling crystal 4 monitored by the temperature detection component 7 and the real-time frequency doubling power data collected by the power collection module to the microcontroller. The microcontroller receives and processes the real-time frequency doubling light power data and the real-time frequency doubling crystal temperature data to obtain the optimal operating temperature of the frequency doubling crystal 4, and controls the temperature control furnace to maintain at this operating temperature, so that the frequency doubling system can ensure its own stability and reliability when the external conditions are harsh or changing.

[0145] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A temperature controlled furnace structure, characterized in that: It comprises a housing (1), a plurality of heat insulating components (2), a crystal seat (3), a frequency doubling crystal (4), a pressing mechanism (5), a heating component (6) and a temperature detecting component (7), wherein: The interior of the shell (1) is hollow, and the two sides thereof are convex outwards; A plurality of heat insulating components (2) are arranged inside the housing (1) and are arranged at intervals; The crystal seat (3) is arranged on a plurality of heat insulating members (2), and the crystal seat (3) is spaced apart from the inner wall of the housing (1), and a groove (300) with two ends passing through is provided on one side of the crystal seat (3); The frequency doubling crystal (4) is arranged in the groove (300), and transmission holes (110) penetrating to the interior are provided at the protrusions on both sides of the housing (1), and the positions of the transmission holes (110) on both sides correspond to the positions of the two ends of the groove (300) respectively, and are used for the incidence and emission of external lasers; A window sheet (12) is arranged in the transmission hole (110) to prevent dust and heat from entering the housing (1); The clamping mechanism (5) is arranged on a side of the crystal seat (3) away from the heat insulating member (2) and is used to longitudinally fix the frequency doubling crystal in the groove (300); The heating element (6) is arranged on a side of the crystal seat (3) close to the heat insulating element (2) and located at the center, and is used to uniformly heat the frequency doubling crystal (4); The temperature detection element (7) is arranged on one side of the crystal seat (3) and is used to monitor the temperature of the frequency doubling crystal (4).

2. The temperature control furnace structure according to claim 1, characterized in that: The outer side of the frequency doubling crystal (4) is wrapped with a tin-indium alloy film, which is used to fix the frequency doubling crystal (4) and the crystal seat (3) by hot melting, and the size of the frequency doubling crystal (4) matches that of the groove (300), so that the frequency doubling crystal (4) is tightly fixed in the groove (300).

3. The temperature control furnace structure according to claim 1, characterized in that: The housing (1) comprises a backing plate (101) and an outer shell (102), wherein: The outer shell (102) is fixed on the backing plate (101) by means of bolts, and the outer shell (102) is a stainless steel heat-insulating shell; The plurality of heat insulating components (2) are all fixed on the backing plate (101) and are all located inside the outer shell (102); the heat insulating components (2) are made of glass.

4. The temperature control furnace structure according to claim 3, characterized in that: The clamping mechanism (5) comprises a pressure cover (51), an upper cover (52), a plurality of first elastic members (53), a plurality of second elastic members (54) and a pressure block (55), wherein: The pressure cover (51) is arranged on a side of the crystal seat (3) away from the thermal insulation member (2); The plurality of first elastic members (53) are all arranged on one side of the pressure cover (51) close to the crystal seat (3) and are arranged at even intervals, and the other side of the plurality of first elastic members (53) extends into the groove (300); The pressing block (55) is fixed between the first elastic members (53) on one side away from the pressing cover (51), and the pressing block (55) is located in the groove (300) and abuts against the frequency doubling crystal (4); The upper cover (52) is fixed on a side of the pressure cover (51) away from the first elastic member (53); The plurality of second elastic members (54) are all arranged on a side of the upper cover (52) away from the crystal seat (3) and are arranged at even intervals, and the other sides of the plurality of second elastic members (54) are all in contact with the inner wall of the outer shell (102).

5. The temperature control furnace structure according to claim 3, characterized in that: It also includes a mounting base (8), a PCB adapter plate (9) and a plurality of terminal posts (10), wherein: The PCB adapter plate (9) is arranged on the mounting seat (8); The backing plate (101) abuts against a side of the PCB adapter plate (9) away from the mounting seat (8); the housing (102) is fixed to the mounting seat (8) by bolts penetrating the backing plate (101) and the PCB adapter plate (9); and a avoidance hole (100) corresponding to the position of the terminal (10) is provided on the backing plate (101); The plurality of terminal posts (10) are arranged on a side of the PCB adapter plate (9) away from the mounting seat (8) and are electrically connected to the PCB adapter plate (9). The plurality of terminal posts (10) respectively pass through corresponding avoidance holes (100) and are electrically connected to the heating element (6) and the temperature detection element (7).

6. The temperature control furnace structure according to claim 1, characterized in that: A mounting groove is provided in the middle of the side surface of the crystal seat (3), and the temperature detection component (7) is arranged in the mounting groove and is adjacent to the frequency doubling crystal (4). The temperature detection component (7) is fixed in the mounting groove by bolts through a fixing component (11).

7. A method for controlling a temperature-controlled furnace structure, implemented by using the temperature-controlled furnace structure according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, collecting the optical signal output by the temperature-controlled furnace to the power collection module, so that the power collection module obtains real-time frequency-multiplied power data at different working temperatures corresponding to the output optical signal; S2, constructing an initial model based on the collected real-time frequency-multiplied power data at different operating temperatures, and determining the parameters of the target model by the least square method to obtain the target model; S3, using genetic algorithm to optimize the target model, solving for the optimal working temperature, and controlling the working temperature of the temperature control furnace according to the optimal working temperature.

8. The control method of the temperature control furnace structure according to claim 7, characterized in that: In step S1, real-time frequency doubling power data at different operating temperatures are collected, and real-time temperature data of the frequency doubling crystal (4) and real-time power data of the optical signal output by the frequency doubling crystal (4) are collected through a temperature detection component (7) and a power collection module. A collection time step is preset, and real-time temperature data and real-time power data are collected according to the time step, and the real-time temperature data and real-time power data are matched one to one.

9. The control method of the temperature control furnace structure according to claim 8, characterized in that: Step S2 includes the following sub-steps: S21, based on the real-time frequency-multiplied power data collected at different operating temperatures, construct an initial model, the expression is: Where θ0,θ1,...,θ n is the constant parameter to be solved, x is the temperature variable, y is the power variable; S22, given the initial value of the constant parameter to be solved, defined as θ0 (0) ,θ1 (0) ,...,θ n (0) ; S23, construct the residual sum of squares function, the expression is as follows: Where S(θ) is the residual sum of squares, y i is the frequency-multiplied power data at the i-th operating temperature; S24, find the gradient of the residual sum of squares with respect to θ, the expression is: In the formula, θ j is the jth constant parameter to be solved, j = 1, 2, ..., n, is the initial model f with respect to the parameter θ j The partial derivative of i The value at S25, iterate the initial model and update the constant parameters to be solved until convergence stops, determine the parameters of the target model, obtain the target model, and update the expression as follows: In the formula, θ (k) is the parameter value at the kth iteration, and α is the learning rate.

10. The control method of the temperature control furnace structure according to claim 9, characterized in that: Step S3 includes the following sub-steps: S31, using binary coding to encode the working temperature as individuals in the genetic algorithm; S32, randomly generate a group of initial populations, each individual represents a working temperature, set the size of the population to N, and set the range of the working temperature to [T min ,T max ], a randomly generated set of initial populations is defined as P0 = {T1, T2, ..., T N }; S33, using the target model to evaluate the fitness of each operating temperature in the initial population, is expressed as: F(T)=f(T) In the formula, F(T) is the fitness of the working temperature, and f(T) is the fitness function; S34, using the roulette wheel selection method, determines the probability of being selected according to the fitness value of the individual, and the expression is: In the formula, p(m) is the probability of the mth individual being selected; S35, pair the selected individuals in pairs, and perform crossover operation on the paired individuals to generate new individuals. The expression is: T′ m =βT m +(1-β)T q T′ q =βT q +(1-β)T m In the formula, β is the crossover rate, and its value range is between 0 and 1; S36, random changes are made to each newly generated individual, and the expression is: T″ m =T′ m +δ In the formula, δ is a random number used to ensure T″ m In [T min , T max ] within the scope; S37, using the newly generated individuals after crossover and mutation to replace the original individuals in the old population to form a new population; S38, repeating steps S33 to S37 for iteration until the fitness value reaches convergence and stops, decoding the binary representation of the optimal individual into the working temperature, and obtaining the optimal working temperature.

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