Spot determination method and device of laser beam, electronic equipment and storage medium

Abstract

The application provides a laser beam spot determination method and device, electronic equipment and storage medium. The laser beam spot determination method comprises the following steps: determining an energy density threshold of a to-be-emitted laser beam under a given output power and repetition frequency; determining a target energy of the to-be-emitted laser beam based on the energy density threshold and a preset correction parameter; and determining a focused spot of the to-be-emitted laser beam based on the output power, the repetition frequency and the target energy, so that the focused spot acts on a to-be-cut object to realize cutting. The technical solution provided by the application can avoid causing secondary injury and improve the cutting accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser, in particular to a laser beam spot determination method and device, electronic equipment and storage medium. BACKGROUND

[0002] Laser cutting technology is widely used in the processing of metal and non-metal materials, which can improve the processing quality of the processed objects, for example, the high precision and cold processing characteristics of femtosecond laser, which are widely used in microelectronics, aerospace and other industrial fields, and can also be applied to medical treatment, such as myopia correction, brain surgery, etc. However, in the medical field, the processing of non-metal materials such as orthopedic cutting requires controlling the temperature when laser acts on the object, and selecting the appropriate laser source is different from the requirements of industrial processing field, which needs to be analyzed according to the specific requirements.

[0003] At present, due to the inability to determine the energy required by the laser when cutting the object and the spot of the laser beam, it is impossible to achieve object cutting or secondary injury caused by the burning of the object after cutting, especially in the medical field such as bone cutting. Higher temperature can cause irreversible damage to bone plates, which is a fatal injury. Therefore, there is no precedent for applying femtosecond laser to orthopedic treatment such as bone cutting. Therefore, how to achieve object cutting by laser while avoiding secondary injury and improving cutting accuracy has become a problem to be solved. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a laser beam spot determination method and device, electronic equipment and storage medium, which can determine the target energy of the to-be-emitted laser beam by the energy density threshold of the to-be-emitted laser beam and the preset correction parameter, so as to determine the focused spot of the to-be-emitted laser beam based on the output power, the repetition frequency and the target energy, so as to realize cutting by acting the focused spot on the to-be-cut object, avoid causing secondary injury, and improve the cutting accuracy.

[0005] The present application mainly includes the following aspects:

[0006] In a first aspect, the present application provides a laser beam spot determination method, which comprises:

[0007] Determine the energy density threshold of the to-be-emitted laser beam under a given output power and repetition frequency;

[0008] Determine the target energy of the to-be-emitted laser beam based on the energy density threshold and the preset correction parameter;

[0009] determine a focused spot of the laser beam to be emitted based on the output power, the repetition frequency and the target energy, so as to realize cutting by acting on the object to be cut by the focused spot.

[0010] Further, the energy density threshold value comprises a first energy density threshold value and a second energy density threshold value; the first energy density threshold value in the energy density threshold value is determined by the following steps:

[0011] obtain a minimum unit volume energy required for ablation of the object to be cut and a predetermined absorption coefficient of the object to be cut;

[0012] determine the reciprocal of the absorption coefficient of the object to be cut as the thickness of the tissue absorption layer of the object to be cut;

[0013] determine the product of the minimum unit volume energy and the thickness of the tissue absorption layer as the first energy density threshold value in the energy density threshold value.

[0014] Further, the absorption coefficient of the object to be cut is determined by the following steps:

[0015] obtain the density of each component in the object to be cut, the proportion of each component in the object to be cut, the component absorption coefficient of each component in the object to be cut, and the density coefficient of the object to be cut;

[0016] for each component in the object to be cut, divide the product of the component absorption coefficient of the component and the proportion of the component by the density of the tissue component to obtain a second parameter corresponding to the tissue component;

[0017] add the second parameters corresponding to each component in the object to be cut to obtain a target parameter of the object to be cut;

[0018] determine the product of the target parameter of the object to be cut and the density coefficient of the object to be cut as the absorption coefficient of the object to be cut.

[0019] Further, the second energy density threshold value in the energy density threshold value is determined by the following steps:

[0020] obtain a preset thermal diffusion coefficient and a thermal relaxation time;

[0021] determine the product of the minimum unit volume energy required for ablation of the object to be cut, the absorption coefficient of the object to be cut, the thermal diffusion coefficient and the thermal relaxation time as an energy parameter;

[0022] determine a preset multiple of the energy parameter as the second energy density threshold value in the energy density threshold value.

[0023] Further, the step of determining the focused spot of the laser beam to be emitted based on the output power, the repetition frequency and the target energy comprises:

[0024] determining a quotient of the output power and the repetition frequency as the emission energy of the laser beam to be emitted based on the output power and the repetition frequency;

[0025] determining a quotient of the ratio of the emission energy and the target energy and a quotient of pi as a first parameter;

[0026] determining a value obtained by taking a square root of the first parameter as the focused spot of the laser beam to be emitted.

[0027] Further, the step of determining the target energy of the laser beam to be emitted based on the energy density threshold and a preset correction parameter comprises:

[0028] determining an energy density threshold with a maximum value among the first energy density threshold and the second energy density threshold based on the first energy density threshold and the second energy density threshold in the energy density threshold;

[0029] determining a sum of the energy density threshold with the maximum value and a preset correction parameter as the target energy of the laser beam to be emitted.

[0030] In a second aspect, an embodiment of the present application further provides a spot determination device of a laser beam, the spot determination device comprising:

[0031] a first determination module configured to determine an energy density threshold of a laser beam to be emitted under a given output power and repetition frequency;

[0032] a second determination module configured to determine a target energy of the laser beam to be emitted based on the energy density threshold and a preset correction parameter;

[0033] a third determination module configured to determine a focused spot of the laser beam to be emitted based on the output power, the repetition frequency and the target energy, so as to realize cutting by acting the focused spot on an object to be cut.

[0034] Further, the energy density threshold comprises a first energy density threshold and a second energy density threshold; when the first determination module is used to determine the first energy density threshold among the energy density thresholds, the first determination module is specifically configured to:

[0035] obtain a minimum unit volume energy required for ablation of the object to be cut and a predetermined absorption coefficient of the object to be cut;

[0036] determine the reciprocal of the absorption coefficient of the object to be cut as a thickness of a tissue absorption layer of the object to be cut;

[0037] determine a product of the minimum unit volume energy and the thickness of the tissue absorption layer as a first energy density threshold in the energy density threshold.

[0038] In a third aspect, an electronic device is provided. The electronic device includes a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory through the bus. The machine-readable instructions, when executed by the processor, perform the steps of the laser beam spot determination method described above.

[0039] In a fourth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the steps of the laser beam spot determination method described above are performed.

[0040] The laser beam spot determination method, device, electronic device, and storage medium provided by the embodiments of the present application include: determining an energy density threshold of a laser beam to be emitted under a given output power and repetition frequency; determining a target energy of the laser beam to be emitted based on the energy density threshold and a preset correction parameter; and determining a focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy, so as to act on an object to be cut by the focused spot to achieve cutting.

[0041] In this way, the energy density threshold of the laser beam to be emitted and the preset correction parameter are used to determine the target energy of the laser beam to be emitted, so as to determine the focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy, so as to act on the object to be cut by the focused spot to achieve cutting, thereby avoiding secondary injury and improving the cutting accuracy.

[0042] To make the above objectives, features and advantages of the present application more obvious and understandable, the following will describe preferred embodiments in detail, with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0043] To make the above objectives, features and advantages of the present application more obvious and understandable, the following will describe preferred embodiments in detail, with reference to the accompanying drawings.

[0044] Figure 1 A flow chart of a method for determining a laser beam spot is shown according to an embodiment of the present application.

[0045] Figure 2 A flow chart of another method for determining a laser beam spot is shown according to an embodiment of the present application.

[0046] Figure 3 A structure diagram of a device for determining a laser beam spot is shown according to an embodiment of the present application.

[0047] Figure 4 A structure diagram of another device for determining a laser beam spot is shown according to an embodiment of the present application.

[0048] Figure 5 A structure diagram of an electronic device is shown according to an embodiment of the present application. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of description and illustration, and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn according to the actual proportions. The flow charts show the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flow charts can not be implemented in sequence, and the steps without logical context relationship can be reversed in sequence or implemented simultaneously. In addition, one or more other operations can be added to the flow charts or removed from the flow charts by those skilled in the art under the guidance of the content of the present application.

[0050] In addition, the described embodiments are only some of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0051] In order to enable those skilled in the art to use the content of the present application, the following implementation is given in combination with a specific application scenario "determination of a laser beam spot". Those skilled in the art can apply the general principles defined herein to other embodiments and application scenarios without departing from the spirit and scope of the present application.

[0052] The methods, apparatus, electronic devices, or computer-readable storage media described in this application can be applied to any scenario where it is necessary to determine the spot of a laser beam. This application does not limit the specific application scenario. Any scheme that uses a laser beam spot determination method, apparatus, electronic device, and storage medium provided in this application is within the protection scope of this application.

[0053] It is worth noting that laser cutting technology is widely used in the processing of both metallic and non-metallic materials, which can improve the processing quality of the workpieces. For example, the high precision and cold processing characteristics of femtosecond lasers have led to their widespread use in industrial fields such as microelectronics and aerospace. They can also be applied in the medical field, such as myopia correction and neurosurgery. However, in the medical field, in the processing of non-metallic materials, such as orthopedic cutting, it is necessary to control the temperature of the laser when it interacts with the material, and the choice of laser source is different from that in industrial processing. It requires specific analysis based on comprehensive requirements.

[0054] Currently, due to the inability to determine the energy required for laser cutting and the laser beam spot size, secondary damage such as failure to cut or charring of the cut object can occur. This is especially true in medical fields such as bone cutting, where high temperatures can cause irreversible and even fatal damage to bone platelets. Therefore, there is no precedent for applying femtosecond lasers to orthopedic treatments such as bone cutting. Thus, how to achieve laser cutting while avoiding secondary damage and improving cutting accuracy has become an urgent problem to be solved.

[0055] Based on this, this application proposes a method, apparatus, electronic device, and storage medium for determining the spot of a laser beam. The spot determination method includes: determining an energy density threshold of the laser beam to be emitted under a given output power and repetition frequency; determining a target energy of the laser beam to be emitted based on the energy density threshold and a preset correction parameter; and determining a focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy, so as to apply the focused spot to the object to be cut to achieve cutting.

[0056] In this way, the technical solution provided in this application can determine the target energy of the laser beam to be emitted by using the energy density threshold and preset correction parameters. Then, based on the output power, repetition frequency and target energy, the focused spot of the laser beam to be emitted can be determined so that the focused spot can be applied to the object to be cut to achieve cutting, avoiding secondary damage and improving the cutting accuracy.

[0057] To facilitate understanding of this application, a brief description of the prior art is provided first. For example, in the medical field, orthopedic surgery is a specialty within medical institutions, encompassing trauma and spinal surgery. It is a specialized department dedicated to the diagnosis and treatment of various types of finger, palm, and multiple finger amputations, replantation, various types of flap transplantation, nerve repair, congenital limb deformities, brachial plexus injuries, and nerve entrapment. With the development and advancement of science and technology, orthopedic surgery faces increasingly higher demands in treatment, diagnosis, and repair. Orthopedic treatment involves extensive cutting and drilling of fixation holes. Traditional orthopedic cutting methods include wire saws, oscillating saws, and ultrasonic bone scalpels, among others. The ultrasonic bone scalpel is one of the most precise tools, used when there are important blood vessels and nerves nearby. These traditional mechanical tools not only require high levels of skill from the surgeon but also demand intense concentration, making them typical experience-based procedures. Furthermore, the noise and unpredictability during mechanical operation pose significant safety hazards, potentially leading to secondary injuries to the patient due to operational errors. In addition, existing orthopedic cutting devices are prone to causing unnecessary harm to patients due to errors in judging the cutting location or insufficient precision. Therefore, there is a need for a highly precise, unique, non-contact, controllable, and visualized disruptive technology to provide doctors with a clinical orthopedic cutting method and device to solve the many problems mentioned in the background.

[0058] Secondly, laser technology is considered an indispensable tool for human survival and development in an intelligent society. Laser cutting, widely used in cutting, involves focusing a laser beam onto the surface of a material to melt it. Simultaneously, compressed gas, coaxial with the laser beam, blows away the molten material, creating a relative motion between the laser beam and the material along a specific trajectory, thus forming a cut of a certain shape. Laser cutting technology is widely used in the processing of both metallic and non-metallic materials, improving the quality of the processed objects. Laser cutting methods include vaporization cutting, melting cutting, laser flame cutting, and controlled fracture cutting. Among these, vaporization cutting best meets the application requirements of lasers in orthopedic cutting. Since human bone contains water, hydroxyapatite, and collagen, it is considered a non-metallic material in laser cutting. Furthermore, the temperature during laser interaction must be controlled. Therefore, the choice of laser source for new devices used in orthopedic surgery differs from that in industrial processing and requires specific analysis based on comprehensive requirements.

[0059] In clinical practice, laser technology, acting as an energy carrier, directly targets biological tissues, producing various physicochemical effects (thermal, pressure, optical, and electromagnetic field effects). These effects lead to tissue vaporization, melting, high-temperature decomposition, and ejection, a phenomenon known as "tissue ablation." Laser ablation is primarily used for the removal of both soft and hard biological tissues. Compared to traditional surgical instruments, laser ablation technology offers advantages such as minimal vibration, non-contact surgery, precise cutting, and minimal invasiveness. Hard tissues like bone can be considered composite materials, composed of calcium salts providing compressive strength and soft connecting tissues providing tensile strength and elasticity. This unique structural characteristic of bone tissue determines that its ablation mechanism differs from that of soft biological tissues. Traditional ablation models, such as photochemical ablation, photothermal ablation, and photo-induced plasma ablation, cannot explain the ablation behavior of hard biological tissues. Early research suggested that the ablation of hard biological tissues required the vaporization of all material components, necessitating sufficiently high temperatures within the tissue to vaporize the mineral components (above 1500°C) and soft connecting tissues (approximately 300°C). When a laser acts on the surface of cortical bone material, the temperature of the irradiated area rises instantaneously. When the soft connective tissue components are vaporized rapidly enough, the resulting vaporization gas flow carries away and removes apatite microcrystals from the crater, creating an ablation depression. Simultaneously, a damaged layer with significant carbonization is formed on the tissue surface. To accelerate the removal of micron-sized calcium salt particles from the crater, the vaporization gas flow velocity of the soft components must be on the same order of magnitude as the speed of sound. In the field of laser orthopedic cutting, whether in clinical treatment, preclinical research, or basic research, laser processing requires consideration of factors such as laser wavelength, energy (or power), pulse width, spectrum, pulse frequency, polarization, and phase. It also necessitates consideration of the focusing system, scanning speed and direction, the composition, structure, and morphology of the processed material, and even the environmental conditions such as temperature and atmosphere. Research indicates that in laser orthopedic applications, laser wavelength, pulse width, and energy and power densities are the three most critical parameters.

[0060] Finally, laser processing can be considered a laser-induced reaction, which in principle is divided into induced molecular vibration and electronic excitation. The former is a thermal reaction, while the latter interacts with the chemical bonds associated with the electrons of the outer shell of atoms constituting matter. Near-infrared femtosecond laser processing achieves spatially selective manipulation of microstructures through multiphoton processes without affecting the surface structure, which is another advantage of femtosecond laser processing. Femtosecond lasers have many advantages, primarily in their high precision. Due to their very short pulse width, femtosecond lasers can achieve extremely high peak power (pulse energy / pulse width) with relatively low pulse energy. When further focused on the material using an objective lens, the high energy density near the focal point can induce various strong nonlinear effects. Femtosecond laser processing has the following advantages: ① minimal thermal impact on the workpiece; ② the ability to process materials that are difficult to process with other lasers, such as transparent materials, high-melting-point materials, thermal decomposers, and heat-deformable materials; ③ the ability to control the depth direction of the internal structure using a focused beam, thereby achieving internal molecular bond breaking and realizing "cold processing." Under laser irradiation, the time for electrons to absorb photons and be excited is in the fs range (during the pulse interaction). Subsequently, electron-phonon coupling occurs, and the time for energy transfer to the crystal lattice and the lattice to reach thermal equilibrium is on the order of several to tens of ps. The timescales for thermal diffusion and material melting vary depending on the material, generally ranging from tens to hundreds of ps. The time for surface ablation varies from hundreds of ps to nanoseconds. Under nanosecond and picosecond laser irradiation, the laser energy deposited in the electron gas is transferred to the crystal lattice within the time of the laser pulse irradiation, causing the material to heat, melt, or even ablate, with a significant thermal effect. Due to the high precision and "cold processing" characteristics of femtosecond lasers, they can be widely used in industrial fields such as microelectronics and aerospace, as well as in medicine, such as myopia correction and neurosurgery. When femtosecond lasers act on metals, because the pulse width of the femtosecond laser is smaller than the timescale of electron-phonon interaction, the laser energy absorbed by the electrons does not have time to be transferred to the ions before the pulse ends. Therefore, the electron temperature is very high while the ion temperature is still very low, making femtosecond laser ablation of metals a non-equilibrium ablation. The two-temperature model and its improved version show that the temperature change of the lattice is related to lattice thermal conduction and electron-lattice coupling. Under the action of high-intensity (≥10¹⁴ W / cm²) femtosecond lasers, the ionization of the material is completed before the end of the pulse duration (~100 fs), at which point the ablation mechanism of metals and dielectrics is the same. The femtosecond laser is also related to the laser pulse frequency. When numerous femtosecond laser pulses are strung together to form a quasi-continuous pulse array, i.e., when the pulse frequency is very high, the residual heat from femtosecond laser processing will produce a thermal accumulation effect. Controlling the repetition frequency holds promise for achieving the fabrication of three-dimensional structures that combine the characteristics of femtosecond lasers and long-pulse or continuous lasers, exhibiting both multiphoton absorption and thermal effects, further expanding the types of micro / nano structures formed and the functions of materials.During the interaction between femtosecond lasers and materials, the timescale of photon heating of electrons (<1 ps) and electron-phonon coupling (ps) is much smaller than the timescale of thermal diffusion (>0.1 ns). This results in residual heat from laser processing generating a thermal field. For low-repetition-rate femtosecond lasers, due to the longer interval between pulses, the temperature of the laser-focused region has already dropped to ambient temperature by the time the next pulse reaches the material. However, for high-repetition-rate femtosecond lasers, the shorter interval between pulses means that when this interval is shorter than the time required for the thermal field generated by laser irradiation to diffuse, the thermal field generated by the previous pulse has not completely dissipated by the time the next pulse reaches the sample, leading to heat accumulation. As the irradiation time increases and the number of laser pulses increases, the temperature of the laser-focused region gradually rises until a dynamic equilibrium is reached. While the thermal field generated during high-repetition-rate femtosecond laser irradiation increases the size of laser-induced micro / nanostructures, it is also crucial for the formation of certain micro / nanostructures.

[0061] Specifically, the technical solutions provided in this application will be described in detail below with reference to specific embodiments.

[0062] Please see Figure 1 , Figure 1 A flowchart of a laser beam spot determination method provided in an embodiment of this application is shown below. Figure 1 As shown, the spot determination method includes:

[0063] S101. Given the output power and repetition frequency, determine the energy density threshold of the laser beam to be emitted;

[0064] In this step, the energy density threshold includes a first energy density threshold and a second energy density threshold.

[0065] It should be noted that the steps for determining the first energy density threshold in the energy density threshold calculation are detailed in the following section. Figure 2 , Figure 2 A flowchart of another laser beam spot determination method provided in the embodiments of this application is shown below. Figure 2 As shown, the first energy density threshold in the energy density threshold is determined through the following steps:

[0066] S201. Obtain the minimum unit volume energy required for the ablation of the object to be cut and the predetermined absorption coefficient of the object to be cut;

[0067] In this step, the absorption coefficient of the object to be cut is determined through the following steps:

[0068] 1) Obtain the density of each component in the object to be cut, the proportion of each component in the object to be cut, the component absorption coefficient of each component in the object to be cut, and the density coefficient of the object to be cut;

[0069] In this step, the object to be cut can be made of different materials, including metal and non-metal materials. This embodiment can cut objects of different materials to improve the applicability of laser beam cutting objects.

[0070] For example, in non-metallic materials, non-metallic materials include things like eyes and bones; for instance, when cutting bones, the object to be cut is the flesh and bone, and the components of bones include hydroxyapatite, water, and collagen, etc., and the density ρ of hydroxyapatite is obtained. HA and component absorption coefficient μ HA The density of water and component absorption coefficient Collagen density ρ col and component absorption coefficient μ col and the proportions of hydroxyapatite, water, and collagen (x) HA : x col The density coefficient ρ of bone; Here, the proportion of each component in the object to be cut can be measured in advance by the instrument, the density of each component in the object to be cut can be obtained in advance by consulting the literature, the component absorption coefficient of each component in the object to be cut and the density coefficient of the object to be cut can be obtained in advance by experimental data, or determined in advance by historical experience or consulting the literature.

[0071] 2) For each component in the object to be cut, the product of the component absorption coefficient and the proportion of the component is divided by the density of the tissue component to obtain the second parameter corresponding to the tissue component.

[0072] 3) Summing the second parameters corresponding to each component of the object to be cut, we obtain the target parameters of the object to be cut;

[0073] 4) The product of the target parameter of the object to be cut and the density coefficient of the object to be cut is determined as the absorption coefficient of the object to be cut.

[0074] For example, the formula for the bone resorption coefficient is as follows:

[0075]

[0076] Where, μ a ρ is the bone absorption coefficient; ρ is the bone density coefficient; ρ HA The density of hydroxyapatite; μ HAThe component absorption coefficient of hydroxyapatite; The density of water; ρ is the absorption coefficient of water components; col The density of collagen; μ col x represents the absorption coefficient of collagen components. HA : x col The percentages of hydroxyapatite, water, and collagen.

[0077] For example, the density of hydroxyapatite is taken as ρ. HA =3.15g / cm 3 The density of water is taken as The density of collagen is taken as ρ col =1.2g / cm 3 The percentage of each component is taken as x. HA : x col = 0.65:0.10:0.25; The component absorption coefficient of hydroxyapatite is taken as μ. HA =4572cm -1 The water component absorption coefficient is taken as The absorption coefficient of collagen components is taken as μ. col =212cm -1 The density coefficient of bone is taken as ρ = 1.775 g / cm³. 3 For each component, μ HA x HA / ρ HA The second parameter was determined to be the one corresponding to hydroxyapatite; The second parameter corresponding to water is determined; μ col x col / ρ col The second parameter corresponding to collagen is determined; the second parameters corresponding to each component of the bone to be cut (hydroxyapatite, water, and collagen) are summed to obtain the target parameters of the bone. The absorption coefficient μ of the bone to be cut is determined by multiplying the target parameter of the bone to be cut by the density coefficient ρ of the bone to be cut. a ,Right now Get μ a =1879cm -1 .

[0078] S202. The reciprocal of the absorption coefficient of the object to be cut is determined as the thickness of the tissue absorption layer of the object to be cut.

[0079] S203. The product of the minimum unit volume energy and the thickness of the tissue absorption layer is determined as the first energy density threshold in the energy density threshold.

[0080] In this step, the reciprocal of the absorption coefficient of the object to be cut, 1 / μ a Let δ be the thickness of the tissue absorption layer of the object to be cut; according to the reference, there is an energy density threshold E for laser ablation of biological hard tissue. th (J / cm 2 ) and power density threshold I th (W / cm 2 Energy density threshold E th (J / cm 2 The first energy density threshold E in ) th1 (J / cm 2 The minimum unit volume energy (W) required for bone to begin ablation th And it is directly proportional to the thickness δ of the tissue absorption layer (i.e., the penetration depth), which can be expressed as:

[0081]

[0082] Among them, W th It is predetermined based on historical experience or experimental data, if W th =1.2J / mm 3 Based on the absorption coefficient μ obtained in step 4) above a =1879cm -1 Then the first energy density threshold W th1 =0.64J / cm 2 .

[0083] Here, the second energy density threshold in the energy density threshold is determined through the following steps:

[0084] 1. Obtain the preset thermal diffusivity and thermal relaxation time;

[0085] 2. The product of the minimum unit volume energy required for the ablation of the object to be cut, the absorption coefficient of the object to be cut, the thermal diffusivity, and the thermal relaxation time is determined as the energy parameter.

[0086] Third, the preset multiple of the energy parameter is determined as the second energy density threshold in the energy density threshold.

[0087] In this step, ablation also requires that the rate of laser energy accumulation within the tissue absorption layer be greater than the rate of heat diffusion to the surrounding tissue. Therefore, laser ablation of biological hard tissue has a power density threshold I. th (W / cm 2 ), can be represented as:

[0088]

[0089] Where, τ T is the thermal relaxation time constant, characterizing the time scale of the thermal diffusion process. Therefore, the prerequisites that must be met simultaneously to obtain clean and effective laser ablation of biological hard tissue can be summarized as follows:

[0090]

[0091]

[0092] Where E is the target energy of the laser beam to be emitted, E th2 For the second energy density threshold, τ L To address the thermal relaxation time of the laser, τ T is the thermal relaxation time for bone; k is the thermal diffusivity.

[0093] For example, referring to the example above, we obtain the pre-set thermal diffusivity k and thermal relaxation time τ. L The minimum unit volume energy (W) required to ablate the bone to be cut th (e.g. W) th =1.2J / mm 3 ), the absorption coefficient μ of the bone to be cut a (e.g. μ) a =1879cm -1 ), thermal diffusivity k (e.g., k = 2.5 × 10⁻⁶) -3 cm 2 / s) and thermal relaxation time τ L (e.g., τ) L =500×10 -15 The product of S), i.e., w th ×k×μ a ×τ L The obtained value is (2.8185×10). -9 J / cm 2 If the preset multiple is 4, then the preset multiple of the energy parameter is determined as the second energy density threshold in the energy density threshold, i.e., E. th2 =4×w th ×k×μ a ×τ L The obtained value (E) th2 =1.127×10 -8 J / cm 2 This was determined as the second energy density threshold.

[0094] Here, for high-energy long-pulse lasers, the condition E>E is easily satisfied.th1 However, if the equation E>E cannot be satisfied... th2 The laser energy absorbed by the tissue will rapidly diffuse away from the absorption area as heat, causing thermal damage to surrounding tissues. Similarly, for short-pulse lasers (τ... L >τ T If the single-pulse energy density threshold does not satisfy the equation E>E th1 Laser ablation will also not occur. The absorption coefficient μ can be seen from the two threshold conditions. a For the energy density threshold E th1 and power density threshold I th The effect is exactly the opposite. This is mainly because the laser energy is concentrated in a very thin absorption layer, E th1 With μ a The increase in penetration depth leads to a decrease in temperature gradient, which in turn accelerates heat diffusion, resulting in I... th With μ a The threshold increases with the increase of the repetition rate. The above threshold conditions are mainly for single-pulse (or low repetition frequency) lasers. When analyzing the threshold conditions for high repetition frequency pulsed lasers, the cumulative effect of energy between pulses must also be considered.

[0095] S102. Based on the energy density threshold and the preset correction parameters, determine the target energy of the laser beam to be emitted;

[0096] This step, which involves determining the target energy of the laser beam to be emitted based on an energy density threshold and preset correction parameters, includes:

[0097] S1021. Based on the first energy density threshold and the second energy density threshold in the energy density threshold, determine the energy density threshold with the largest value among the first energy density threshold and the second energy density threshold;

[0098] For example, referring to the example above, the energy density threshold E th The first energy density threshold E in th1 =0.64J / cm 2 And the second energy density threshold E in the energy density threshold th2 =1.127×10 -8 J / cm 2 In E th1 and E th2 In the above, the energy density threshold with the largest value is E. th1 .

[0099] S1022. The sum of the energy density threshold with the largest value and the preset correction parameter is determined as the target energy of the laser beam to be emitted.

[0100] For example, the preset correction parameter is set in advance based on experimental data or historical experience. If the preset correction parameter is 0.03, then the target energy of the laser beam to be emitted is the sum of the maximum energy density threshold and the preset correction parameter, that is, the target energy is E. th1 +0.03 = 0.64 + 0.03 = 0.67 J / cm 2 .

[0101] S103. Based on the output power, the repetition frequency, and the target energy, determine the focused spot of the laser beam to be emitted so that the focused spot can be applied to the object to be cut to achieve cutting.

[0102] It should be noted that the steps for determining the focused spot of the laser beam to be emitted, based on the output power, repetition frequency, and target energy, include:

[0103] S1031. Based on the output power and the repetition frequency, the quotient of the output power and the repetition frequency is determined as the emission energy of the laser beam to be emitted;

[0104] S1032. The ratio of the emitted energy to the target energy and the quotient of pi is determined as the first parameter;

[0105] S1033. The value obtained by taking the square root of the first parameter is determined as the focused spot of the laser beam to be emitted.

[0106] In this step, the formula for the focused spot of the laser beam to be emitted is as follows:

[0107]

[0108] Where E is the target energy of the laser beam to be emitted, P is the output power, f is the repetition frequency, and r is the focused spot of the laser beam to be emitted.

[0109] For example, if P = 50W and f = 200kHz, the target energy E obtained in the example of step S1022 is 0.67J / cm². 2Taking π as 3.14, the focused spot size of the laser beam to be emitted can be calculated as r = 109 μm. This allows the femtosecond laser to emit a laser beam with a focused spot size of 109 μm for cutting bone and flesh. According to experimental data, under the conditions of an output wavelength of 1030 nm, a pulse width of 500 fs, a repetition frequency of 200 kHz, and an output power of 50 W, the preferred data is a negative defocus condition with a focused spot size of 100 μm, which was used to process pig tibias and achieved the required processing effect. Specifically, two types of applications were applied to the pig tibia. One type involved drilling: the geometric dimensions of the drilled holes were 5 mm and the depth was 10 mm. The transverse and longitudinal cross-sectional shapes of the holes met the drilling requirements, and the surface roughness of the holes reached within 3.2, with intact surface structure and unchanged composition. The second category concerns the cutting line: the cutting line width is 1mm, the depth is 1mm, and the length is 20mm. The shape of the wire cut meets the requirements, there is no bone recasting layer, and from the three-dimensional morphology of the hole, there is no recasting layer, the surface structure is intact, and the composition has not changed. Experimental results demonstrate that the solution in this embodiment can overcome the shortcomings of existing bone-cutting techniques, such as secondary irreversible damage caused by excessively high temperatures during processing with traditional tools, uncontrollable cutting shapes, cutting risks, cutting debris, and excessively high temperatures in the processed body. It solves the long-standing problem of orthopedic cutting techniques being limited by the experience of surgeons. Once this application is realized on the tibia, it will be widely used in orthopedic surgery, marking a revolutionary development in orthopedic surgery.

[0110] This application provides a method for determining the spot of a laser beam. The method includes: determining an energy density threshold of the laser beam to be emitted under a given output power and repetition frequency; determining the target energy of the laser beam to be emitted based on the energy density threshold and a preset correction parameter; and determining the focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy, so as to apply the focused spot to the object to be cut to achieve cutting.

[0111] In this way, the technical solution provided in this application can determine the target energy of the laser beam to be emitted by using the energy density threshold and preset correction parameters. Then, based on the output power, repetition frequency and target energy, the focused spot of the laser beam to be emitted can be determined so that the focused spot can be applied to the object to be cut to achieve cutting, avoiding secondary damage and improving the cutting accuracy.

[0112] Based on the same application concept, this application also provides a laser beam spot determination device corresponding to the laser beam spot determination method provided in the above embodiment. Since the principle of the device in this application is similar to the laser beam spot determination method in the above embodiment, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0113] Please see Figure 3 , Figure 4 , Figure 3 This is one of the structural diagrams of a laser beam spot determination device provided in the embodiments of this application. Figure 4 This is a second structural diagram of a laser beam spot determination device provided in an embodiment of this application. Figure 3 As shown, the spot determination device 310 includes:

[0114] The first determining module 311 is used to determine the energy density threshold of the laser beam to be emitted under a given output power and repetition frequency.

[0115] The second determining module 312 is used to determine the target energy of the laser beam to be emitted based on the energy density threshold and the preset correction parameters.

[0116] The third determining module 313 is used to determine the focused spot of the laser beam to be emitted based on the output power, the repetition frequency and the target energy, so as to apply the focused spot to the object to be cut to achieve cutting.

[0117] Optionally, the energy density threshold includes a first energy density threshold and a second energy density threshold; when determining the first energy density threshold, the first determining module 311 is specifically used for:

[0118] The minimum unit volume energy required for the ablation of the object to be cut and the pre-determined absorption coefficient of the object to be cut are obtained.

[0119] The reciprocal of the absorption coefficient of the object to be cut is determined as the thickness of the tissue absorption layer of the object to be cut;

[0120] The product of the minimum unit volume energy and the thickness of the tissue absorption layer is determined as the first energy density threshold in the energy density threshold.

[0121] Optional, such as Figure 4 As shown, the light spot determining device 310 further includes a fourth determining module 314, which is used for:

[0122] The density of each component in the object to be cut, the proportion of each component in the object to be cut, the component absorption coefficient of each component in the object to be cut, and the density coefficient of the object to be cut are obtained.

[0123] For each component in the object to be cut, the product of the component absorption coefficient and the proportion of the component is divided by the density of the tissue component to obtain the second parameter corresponding to the tissue component.

[0124] The target parameters of the object to be cut are obtained by summing the second parameters corresponding to each component in the object to be cut.

[0125] The absorption coefficient of the object to be cut is determined by multiplying the target parameter of the object to be cut by the density coefficient of the object to be cut.

[0126] Optionally, when determining the second energy density threshold in the energy density threshold, the first determining module 311 is specifically used for:

[0127] Obtain the preset thermal diffusivity and thermal relaxation time;

[0128] The product of the minimum unit volume energy required for the ablation of the object to be cut, the absorption coefficient of the object to be cut, the thermal diffusivity, and the thermal relaxation time is determined as the energy parameter.

[0129] The preset multiple of the energy parameter is determined as the second energy density threshold in the energy density threshold.

[0130] Optionally, when the third determining module 313 is used to determine the focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy, the third determining module 313 is specifically used for:

[0131] Based on the output power and the repetition frequency, the quotient of the output power and the repetition frequency is determined as the emission energy of the laser beam to be emitted;

[0132] The ratio of the emitted energy to the target energy to the quotient of pi is determined as the first parameter;

[0133] The value obtained by taking the square root of the first parameter is determined as the focused spot of the laser beam to be emitted.

[0134] Optionally, when the second determining module 312 is used to determine the target energy of the laser beam to be emitted based on the energy density threshold and preset correction parameters, the second determining module 312 is specifically used for:

[0135] Based on the first energy density threshold and the second energy density threshold, determine the energy density threshold with the largest value among the first energy density threshold and the second energy density threshold;

[0136] The sum of the maximum energy density threshold and the preset correction parameter is determined as the target energy of the laser beam to be emitted.

[0137] This application provides a laser beam spot determination device, comprising: a first determination module for determining an energy density threshold of a laser beam to be emitted under a given output power and repetition frequency; a second determination module for determining a target energy of the laser beam to be emitted based on the energy density threshold and a preset correction parameter; and a third determination module for determining a focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy, so as to apply the focused spot to the object to be cut to achieve cutting.

[0138] In this way, the technical solution provided in this application can determine the target energy of the laser beam to be emitted by using the energy density threshold and preset correction parameters. Then, based on the output power, repetition frequency and target energy, the focused spot of the laser beam to be emitted can be determined so that the focused spot can be applied to the object to be cut to achieve cutting, avoiding secondary damage and improving the cutting accuracy.

[0139] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 5 As shown, the electronic device 500 includes a processor 510, a memory 520, and a bus 530.

[0140] The memory 520 stores machine-readable instructions executable by the processor 510. When the electronic device 500 is running, the processor 510 and the memory 520 communicate via the bus 530. When the machine-readable instructions are executed by the processor 510, they can perform the operations described above. Figure 1 as well as Figure 2 The steps of the laser beam spot determination method in the method embodiment shown are described in detail in the method embodiment, and will not be repeated here.

[0141] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 as well as Figure 2 The steps of the laser beam spot determination method in the method embodiment shown are described in detail in the method embodiment, and will not be repeated here.

[0142] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0143] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0144] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0145] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0146] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0147] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining the spot size of a laser beam used for bone cutting, characterized in that, The method for determining the light spot includes: Determine the energy density threshold of the laser beam to be emitted, given the output power and repetition frequency. Based on the energy density threshold and the preset correction parameters, the target energy of the laser beam to be emitted is determined; Based on the output power, the repetition frequency, and the target energy, the focused spot of the laser beam to be emitted is determined so that the focused spot can be applied to the object to be cut to achieve cutting; the formula for the focused spot of the laser beam to be emitted is as follows: E is the target energy of the laser beam to be emitted, P is the output power, f is the repetition frequency, and r is the focused spot of the laser beam to be emitted. The step of determining the target energy of the laser beam to be emitted based on the energy density threshold and preset correction parameters includes: Based on the first energy density threshold and the second energy density threshold, determine the energy density threshold with the largest value among the first energy density threshold and the second energy density threshold; The sum of the energy density threshold with the largest value and the preset correction parameter is determined as the target energy of the laser beam to be emitted; wherein, the preset correction parameter is set to 0.03; The energy density threshold includes a first energy density threshold and a second energy density threshold; the first energy density threshold is determined through the following steps: The minimum unit volume energy required for the ablation of the object to be cut and the pre-determined absorption coefficient of the object to be cut are obtained. The reciprocal of the absorption coefficient of the object to be cut is determined as the thickness of the tissue absorption layer of the object to be cut; The product of the minimum unit volume energy and the thickness of the tissue absorption layer is determined as the first energy density threshold in the energy density threshold. The absorption coefficient of the object to be cut is determined by the following steps: The density of each component in the object to be cut, the proportion of each component in the object to be cut, the component absorption coefficient of each component in the object to be cut, and the density coefficient of the object to be cut are obtained. For each component in the object to be cut, the product of the component absorption coefficient and the proportion of the component is divided by the density of the component to obtain the second parameter corresponding to the component. The target parameters of the object to be cut are obtained by summing the second parameters corresponding to each component in the object to be cut. The absorption coefficient of the object to be cut is determined by multiplying the target parameter of the object to be cut by the density coefficient of the object to be cut. The second energy density threshold in the energy density threshold is determined by the following steps: Obtain the preset thermal diffusivity and thermal relaxation time; The product of the minimum unit volume energy required for the ablation of the object to be cut, the absorption coefficient of the object to be cut, the thermal diffusivity, and the thermal relaxation time is determined as the energy parameter. The preset multiple of the energy parameter is determined as the second energy density threshold in the energy density threshold; The step of determining the focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy includes: Based on the output power and the repetition frequency, the quotient of the output power and the repetition frequency is determined as the emission energy of the laser beam to be emitted; The ratio of the emitted energy to the target energy to the quotient of pi is determined as the first parameter; The value obtained by taking the square root of the first parameter is determined as the focused spot of the laser beam to be emitted.

2. A laser beam spot determination device for bone cutting, characterized in that, The light spot determining device includes: The first determining module is used to determine the energy density threshold of the laser beam to be emitted under a given output power and repetition frequency. The second determining module is used to determine the target energy of the laser beam to be emitted based on the energy density threshold and preset correction parameters. The third determining module is used to determine the focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy, so as to apply the focused spot to the object to be cut to achieve cutting; the formula for the focused spot of the laser beam to be emitted is as follows: E is the target energy of the laser beam to be emitted, P is the output power, f is the repetition frequency, and r is the focused spot of the laser beam to be emitted. When the second determining module is used to determine the target energy of the laser beam to be emitted based on the energy density threshold and preset correction parameters, the second determining module is specifically used for: Based on the first energy density threshold and the second energy density threshold, determine the energy density threshold with the largest value among the first energy density threshold and the second energy density threshold; The sum of the energy density threshold with the largest value and the preset correction parameter is determined as the target energy of the laser beam to be emitted; wherein, the preset correction parameter is set to 0.03; The energy density threshold includes a first energy density threshold and a second energy density threshold; when determining the first energy density threshold, the first determining module is specifically used to: The minimum unit volume energy required for the ablation of the object to be cut and the pre-determined absorption coefficient of the object to be cut are obtained. The reciprocal of the absorption coefficient of the object to be cut is determined as the thickness of the tissue absorption layer of the object to be cut; The product of the minimum unit volume energy and the thickness of the tissue absorption layer is determined as the first energy density threshold in the energy density threshold. The spot determining device further includes a fourth determining module, which is used for: The density of each component in the object to be cut, the proportion of each component in the object to be cut, the component absorption coefficient of each component in the object to be cut, and the density coefficient of the object to be cut are obtained. For each component in the object to be cut, the product of the component absorption coefficient and the proportion of the component is divided by the density of the component to obtain the second parameter corresponding to the component. The target parameters of the object to be cut are obtained by summing the second parameters corresponding to each component in the object to be cut. The absorption coefficient of the object to be cut is determined by multiplying the target parameter of the object to be cut by the density coefficient of the object to be cut. When the first determining module is used to determine the second energy density threshold in the energy density threshold, the first determining module is specifically used for: Obtain the preset thermal diffusivity and thermal relaxation time; The product of the minimum unit volume energy required for the ablation of the object to be cut, the absorption coefficient of the object to be cut, the thermal diffusivity, and the thermal relaxation time is determined as the energy parameter. The preset multiple of the energy parameter is determined as the second energy density threshold in the energy density threshold; When the third determining module is used to determine the focused spot of the laser beam to be emitted based on the output power, the repetition frequency, and the target energy, the third determining module is specifically used for: Based on the output power and the repetition frequency, the quotient of the output power and the repetition frequency is determined as the emission energy of the laser beam to be emitted; The ratio of the emitted energy to the target energy to the quotient of pi is determined as the first parameter; The value obtained by taking the square root of the first parameter is determined as the focused spot of the laser beam to be emitted.

3. An electronic device, characterized in that, include: The device includes a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. The machine-readable instructions are executed by the processor to perform the steps of the laser beam spot determination method as described in claim 1.

4. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the laser beam spot determination method as described in claim 1.

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