A focal length adjustable laser
By controlling the temperature difference between the front and back surfaces of the lens to adjust its curvature and refractive index, and combining this with thermistor feedback, fine-tuning of the focal length is achieved. This solves the problem that traditional laser therapy devices cannot provide precise treatment for different skin thicknesses, thus improving the treatment effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XI AN OE PHOTONICS CO LTD
- Filing Date
- 2022-11-03
- Publication Date
- 2026-08-04
AI Technical Summary
Traditional fractional laser therapy devices have a fixed focal length, which cannot be precisely adjusted to suit the different thicknesses of the epidermis and dermis in different parts of the body, resulting in poor treatment effects.
By controlling the temperature difference between the front and back surfaces of the lens, the radius of curvature and refractive index of the lens can be adjusted. Combined with thermistor feedback, the temperature difference of the microlens array can be adjusted in real time to achieve fine-tuning of the focal length.
It enables precise adjustment of laser penetration depth based on the skin thickness of different areas, improving the effectiveness and accuracy of treatment.
Smart Images
Figure CN115531736B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of laser technology, and more specifically to a laser with adjustable focal length. Background Technology
[0002] Laser applications in the field of medical aesthetics are becoming increasingly diverse. Fractional laser, as a novel laser technology, works on the principle of focal photothermolysis. This involves applying laser light in microbeams to the skin surface, creating microscopic treatment zones (MTZs). This stimulates the proliferation of dermal collagen fibers, improving skin texture and tone. Fractional technology significantly increases the depth and intensity of laser penetration, while virtually eliminating side effects and complications.
[0003] Traditional fractional laser therapy devices have a fixed focal length, which cannot be adjusted to achieve more precise and effective treatment based on the different thicknesses of the epidermis and dermis in different parts of the body.
[0004] Therefore, a laser with adjustable focal length is needed. Summary of the Invention
[0005] This invention addresses the problem of fixed focal length in traditional fractional laser therapy devices by providing a laser with adjustable focal length. It controls the radius of curvature and refractive index of the lens by managing the temperature difference between the front and back surfaces, thereby fine-tuning the focal length. The main control module, based on the user-selected treatment area and the real-time temperature feedback from two thermistors on both sides of the microlens array, controls the input current of two TECs to regulate the temperature difference between the front and back of the microlens, thus controlling the radius of curvature and refractive index and ultimately fine-tuning the focal length. This invention allows for different laser penetration depths at different skin locations by adjusting the laser focal length, enabling more precise and effective treatment by adjusting the focal length to address the varying thicknesses of the epidermis and dermis in different parts of the body.
[0006] The present invention provides a laser with adjustable focal length, including a laser module and a control module electrically connected to the laser module;
[0007] The laser module generates a laser pulse train and outputs it after shaping, focusing, and focal length adjustment. The control module controls the operation of the laser module.
[0008] The laser module includes a laser generation system, a spot shaping system, and a focal length micro-control system arranged sequentially. Both the laser generation system and the focal length micro-control system are electrically connected to the control module. The laser generation system generates a laser pulse train, the spot shaping system shapes the laser pulse train into a spot and outputs it, and the focal length micro-control system focuses the spot and adjusts the focal length under the control of the control module before outputting it. The focal length micro-control system adjusts the focal length by adjusting the temperature difference between the front and rear surfaces of the lens to control the radius of curvature and refractive index of the lens.
[0009] The laser with adjustable focal length according to the present invention, as a preferred embodiment, includes a focal length microcontroller system comprising a first thermal conductive plate, a TEC, a second thermal conductive plate arranged in sequence, a first thermal sensor disposed on the first thermal conductive plate, a second thermal sensor disposed on the second thermal conductive plate, and a microlens array embedded in the middle of the TEC.
[0010] The TEC has a hollow structure, with a microlens array embedded inside. The first thermal conductive sheet is in close contact with the front surface of the TEC, and the second thermal conductive sheet is in close contact with the rear surface of the TEC.
[0011] After receiving the current output from the control module, the TEC transfers the temperature from one side to the other side to create a temperature difference between the two surfaces. The first heat-conducting plate conducts the heat from one side of the TEC to the front of the microlens array, and the second heat-conducting plate conducts the heat from the other side of the TEC to the back of the microlens array. The temperature difference between the front and back of the microlens array causes changes in the radius of curvature and refractive index of the microlens array, thereby adjusting the focal length.
[0012] In a preferred embodiment of the focal length adjustable laser described in this invention, the focal length microcontroller system further includes a controller electrically connected to the TEC, the first thermal sensor, and the second thermal sensor, and the controller is electrically connected to the control module.
[0013] The controller adjusts the temperature difference between the two sides of the TEC by controlling the current output to the TEC. The first and second thermistors transmit the temperature measurement values of the first and second thermal conductive sheets to the controller, respectively. The controller calculates and sets the target value of the temperature difference between the front and rear surfaces of the microlens array based on the control parameters output by the control module. Then, it adjusts the current output to the TEC after comparing the target value with the temperature measurement value, so that the temperature difference between the front and rear surfaces of the microlens array reaches and maintains the target value.
[0014] In a preferred embodiment of the laser with adjustable focal length described in this invention, the microlens array includes at least two microlenses arranged in an array and a spacer groove formed by the curved surfaces of two adjacent microlenses.
[0015] In a preferred embodiment of the laser with adjustable focal length described in this invention, the first thermal conductive sheet includes a hollow first thermal conductive sheet body and a first thermal conductive mesh connected to the hollow portion of the first thermal conductive sheet body. The first thermal conductive sheet body has a hollow sheet-like structure. The first thermal conductive sheet body is tightly attached to the front surface of the TEC and fixed by welding. The first thermal conductive mesh is tightly attached to the front surface of the spacer groove.
[0016] The second thermal conductive sheet includes a hollow second thermal conductive sheet body and a second thermal conductive mesh connected to the hollow part of the second thermal conductive sheet body. The second thermal conductive sheet body has a hollow sheet structure. The second thermal conductive sheet body is in close contact with the rear surface of the TEC and is fixed by welding. The second thermal conductive mesh is in close contact with the rear surface of the spacer groove.
[0017] The first and second temperature-conducting sheet bodies transfer the temperature of the TEC to the first and second temperature-conducting grids, respectively, and the first and second temperature-conducting grids transfer the temperature to the microlens.
[0018] In a preferred embodiment of the laser with adjustable focal length described in this invention, both the first and second thermal conductive sheet bodies are copper discs with square hollow portions. The shape of the square hollow portions corresponds to the shape of the microlens array. The first thermal conductive grid is a copper wire grid interwoven in the hollow structure of the first thermal conductive sheet body, and the second thermal conductive grid is a copper wire grid interwoven in the hollow structure of the second thermal conductive sheet body.
[0019] The first thermal conductive sheet body is fixed to the front surface of the TEC by indium solder, the second thermal conductive sheet body is fixed to the rear surface of the TEC by indium solder, the first thermistor and the first thermal conductive sheet are fixed together by indium solder, and the second thermistor and the second thermal conductive sheet are fixed together by indium solder.
[0020] In a preferred embodiment of the laser with adjustable focal length described in this invention, the microlenses are arranged in an array of n rows and m columns.
[0021] The convex surface of the microlens faces the first thermal conductive plate, and the concave surface faces the second thermal conductive plate. The temperature on the side of the TEC facing the first thermal conductive plate is higher than the temperature on the side facing the second thermal conductive plate.
[0022] In a preferred embodiment of the laser with adjustable focal length described in this invention, the microlens is fixed to the TEC by adhesive bonding.
[0023] The laser with adjustable focal length according to the present invention, as a preferred embodiment, includes the following steps in the method for adjusting the focal length of the laser:
[0024] S1. The control module outputs control parameters to the focal length microcontroller, and the control parameters are the target area for laser output.
[0025] S2. The focal length micro-control system adjusts the lens's radius of curvature and refractive index according to the temperature difference between the front and rear surfaces of the lens based on the control parameters, and outputs the real-time temperature measurement value to the control module.
[0026] S3. The control module compares the temperature measurement value with the target value and adjusts the magnitude of the current output to the focus microcontroller.
[0027] Return to step S2 until the temperature measurement matches the target value.
[0028] In a preferred embodiment of the laser with adjustable focal length described in this invention, in step S1, the control module outputs control parameters to the controller.
[0029] In step S2, the controller converts the control parameters into a target temperature difference and outputs a current of a corresponding magnitude to the TEC according to the target temperature difference. The target temperature difference corresponds to the thickness of the target area. The TEC transfers the temperature on one side to the other side according to the current magnitude, so that a temperature difference is formed on the two surfaces. The first thermal conductive sheet conducts the heat on one side of the TEC to the front of the microlens array, and the second thermal conductive sheet conducts the heat on the other side of the TEC to the back of the microlens array. The temperature difference between the front and back of the microlens array causes the radius of curvature and refractive index of the microlens array to change, thereby adjusting the focal length.
[0030] The first and second thermistors output the temperature measurement values of the first and second thermal conductive sheets to the control module, respectively.
[0031] In step S3, the target value is the temperature difference between the first and second temperature conductive sheets. If the difference in the measured temperature values is greater than the target value, the control module reduces the current output to the TEC. If the difference in the measured temperature values is less than the target value, the control module increases the current output to the TEC.
[0032] The present invention has the following advantages:
[0033] This invention controls the radius of curvature and refractive index of the lens by controlling the temperature difference between the front and back surfaces of the lens, thereby fine-tuning the focal length. The main control module controls the input current of the two TECs based on the real-time temperature feedback from the two thermistors on both sides of the microlens array, according to the different treatment sites selected by the user, to control the temperature difference between the front and back of the microlens, thereby controlling the radius of curvature and refractive index of the lens and fine-tuning the focal length. This invention can achieve different laser penetration depths on different parts of the skin, and can adjust the focal length for more precise and effective treatment based on the different thicknesses of the epidermis and dermis in different parts of the human body. Attached Figure Description
[0034] Figure 1 This is a schematic diagram of a laser with adjustable focal length.
[0035] Figure 2 This is a schematic diagram illustrating the effect of temperature difference on the front and rear surfaces of a focal length adjustable laser lens on deformation.
[0036] Figure 3 This is a schematic diagram of a microcontroller system for a laser with adjustable focal length.
[0037] Figure 4 This is a schematic diagram of the assembled structure of a focal length adjustable laser microcontroller system.
[0038] Figure 5 This is a flowchart illustrating a method for adjusting the focal length of a laser lens.
[0039] Figure label:
[0040] 1. Laser module; 11. Laser generation system; 12. Beam shaping system; 13. Focal length microcontroller system; 131. First thermal conductive sheet; 1311. First thermal conductive sheet body; 1312. First thermal conductive grid; 132. TEC; 133. Second thermal conductive sheet; 1331. Second thermal conductive sheet body; 1332. Second thermal conductive grid; 134. First thermal sensor; 135. Second thermal sensor; 136. Microlens array; 1361. Microlens; 1362. Spacing; 2. Control module. Detailed Implementation
[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0042] Example 1
[0043] like Figure 1 As shown, a focal length adjustable laser includes a laser module 1 and a control module 2 electrically connected to the laser module 1.
[0044] Laser module 1 generates a laser pulse train and outputs it after shaping, focusing, and focal length adjustment. Control module 2 controls the operation of laser module 1.
[0045] Laser module 1 includes a laser generation system 11, a spot shaping system 12, and a focal length microcontroller 13 arranged sequentially. Both the laser generation system 11 and the focal length microcontroller 13 are electrically connected to control module 2. The laser generation system 11 generates a laser pulse train. The spot shaping system 12 shapes the laser pulse train into a laser spot and outputs it. The focal length microcontroller 13 focuses the laser spot and, under the control of control module 2, adjusts the focal length before outputting it. The focal length microcontroller 13 adjusts the focal length by regulating the temperature difference between the front and rear surfaces of the lens to control the radius of curvature and refractive index of the lens. The principle is as follows: Figure 2 As shown;
[0046] like Figure 3 As shown, the focal length microcontroller system 13 includes a first thermal conductive sheet 131, a TEC 132, a second thermal conductive sheet 133 arranged in sequence, a first thermal sensor 134 disposed on the first thermal conductive sheet 131, a second thermal sensor 135 disposed on the second thermal conductive sheet 133, a microlens array 136 embedded in the middle of the TEC 132, and a controller electrically connected to the TEC 132, the first thermal sensor 134, and the second thermal sensor 135. The controller is electrically connected to the control module 2.
[0047] TEC132 has a hollow structure, with a microlens array 136 embedded inside the hollow structure. The first thermal conductive sheet 131 is in close contact with the front surface of TEC132, and the second thermal conductive sheet 133 is in close contact with the rear surface of TEC132.
[0048] After receiving the current output by the controller, TEC132 transfers the temperature on one side to the other side to create a temperature difference between the two surfaces. The first heat-conducting plate 131 conducts the heat from one side of TEC132 to the front side of the microlens array 136, and the second heat-conducting plate 133 conducts the heat from the other side of TEC132 to the back side of the microlens array 136. The temperature difference between the front and back sides of the microlens array 136 causes changes in the radius of curvature and refractive index of the microlens array 136, thereby adjusting the focal length.
[0049] The controller adjusts the temperature difference between the two sides of TEC132 by controlling the current output to TEC132. The first thermistor 134 and the second thermistor 135 transmit the temperature measurement values of the first temperature conductor 131 and the second temperature conductor 133 to the controller, respectively. The controller calculates and sets the target value of the temperature difference between the front and rear surfaces of the microlens array 136 according to the control parameters output by the control module 2. Then, it adjusts the current output to TEC132 after comparing the target value with the temperature measurement value, so that the temperature difference between the front and rear surfaces of the microlens array 136 reaches and maintains the target value.
[0050] The microlens array 136 includes at least two microlenses 1361 arranged in an array and a spacer groove 1362 formed by the curved surfaces of two adjacent microlenses 1361.
[0051] The first thermal conductive sheet 131 includes a hollow first thermal conductive sheet body 1311 and a first thermal conductive mesh 1312 connected to the hollow part of the first thermal conductive sheet body 1311. The first thermal conductive sheet body 1311 is a hollow sheet structure. The first thermal conductive sheet body 1311 is in close contact with the front surface of TEC132 and is fixed by welding. The first thermal conductive mesh 1312 is in close contact with the front surface of the spacer groove 1362.
[0052] like Figure 4As shown, the second thermal conductive sheet 133 includes a hollow second thermal conductive sheet body 1331 and a second thermal conductive mesh 1332 connected to the hollow part of the second thermal conductive sheet body 1331. The second thermal conductive sheet body 1331 has a hollow sheet structure. The second thermal conductive sheet body 1331 is in close contact with the rear surface of the TEC 132 and is fixed by welding. The second thermal conductive mesh 1332 is in close contact with the rear surface of the spacer groove 1362.
[0053] The first temperature-conducting sheet body 1311 and the second temperature-conducting sheet body 1331 respectively transfer the temperature of TEC132 to the first temperature-conducting grid 1312 and the second temperature-conducting grid 1332, and the first temperature-conducting grid 1312 and the second temperature-conducting grid 1332 transfer the temperature to the microlens 1361.
[0054] The first thermal conductive sheet body 1311 and the second thermal conductive sheet body 1331 are both copper discs with square hollow portions. The shape of the square hollow portions corresponds to the shape of the microlens array 136. The first thermal conductive grid 1312 is a copper wire grid interwoven in the hollow structure of the first thermal conductive sheet body 1311, and the second thermal conductive grid 1332 is a copper wire grid interwoven in the hollow structure of the second thermal conductive sheet body 1331.
[0055] The first thermal conductive sheet body 1311 is fixed to the front surface of TEC132 by indium solder, the second thermal conductive sheet body 1331 is fixed to the rear surface of TEC132 by indium solder, the first thermal sensor 134 and the first thermal conductive sheet 131 are fixed together by indium solder, and the second thermal sensor 135 and the second thermal conductive sheet 133 are fixed together by indium solder.
[0056] The microlenses 1361 are arranged in an array of n rows and m columns;
[0057] The convex surface of the microlens 1361 faces the first thermal conductive sheet 131 and the concave surface faces the second thermal conductive sheet 133. The temperature of the side of TEC132 facing the first thermal conductive sheet 131 is higher than the temperature of the side facing the second thermal conductive sheet 133.
[0058] Microlens 1361 and TEC132 are fixed together by adhesive bonding;
[0059] like Figure 5 As shown, the method for adjusting the focal length of a laser includes the following steps:
[0060] S1. Control module 2 outputs control parameters to the controller, the control parameters being the target area for laser output; control module 2 outputs current to TEC132.
[0061] S2, the focal length micro-control system 13 adjusts the lens's radius of curvature and refractive index by adjusting the temperature difference between the front and rear surfaces of the lens, and outputs the real-time temperature measurement value to the control module 2;
[0062] The controller converts the control parameters into a target temperature difference and outputs a current of a corresponding magnitude to the TEC according to the target temperature difference. The target temperature difference corresponds to the thickness of the target area. The TEC transfers the temperature on one side to the other side according to the current magnitude, so that a temperature difference is formed on the two surfaces. The first heat-conducting plate 131 conducts the heat on one side of the TEC 132 to the front side of the microlens array 136, and the second heat-conducting plate 133 conducts the heat on the other side of the TEC 132 to the back side of the microlens array 136. The temperature difference between the front and back sides of the microlens array 136 causes the radius of curvature and refractive index of the microlens array 136 to change, thereby adjusting the focal length.
[0063] The first thermal sensor 134 and the second thermal sensor 135 respectively output the temperature measurement values of the first temperature conductive sheet 131 and the second temperature conductive sheet 133 to the control module 2;
[0064] S3, Control module 2 compares the temperature measurement value with the target value and adjusts the magnitude of the current output to the focal length microcontroller 13;
[0065] Return to step S2 until the temperature measurement matches the target value;
[0066] The target value is the temperature difference between the first temperature conductor 131 and the second temperature conductor 133. If the difference in the measured temperature values is greater than the target value, the control module 2 reduces the current output to the TEC132. If the difference in the measured temperature values is less than the target value, the control module 2 increases the current output to the TEC132.
[0067] Example 2
[0068] A focal length adjustable laser includes a laser module 1 and a control module 2 electrically connected to the laser module 1;
[0069] Laser module 1 generates a laser pulse train and outputs it after shaping, focusing, and focal length adjustment. Control module 2 controls the operation of laser module 1.
[0070] The laser module 1 includes a laser generation system 11, a spot shaping system 12, and a focal length micro-control system 13 arranged sequentially. Both the laser generation system 11 and the focal length micro-control system 13 are electrically connected to the control module 2. The laser generation system 11 generates a laser pulse train. The spot shaping system 12 shapes the laser pulse train into a spot and outputs it. The focal length micro-control system 13 focuses the spot and adjusts the focal length under the control of the control module 2 before outputting it. The focal length micro-control system 13 adjusts the focal length by adjusting the temperature difference between the front and rear surfaces of the lens to control the radius of curvature and refractive index of the lens.
[0071] like Figure 2As shown, when there is a temperature difference between the front and back surfaces of a lens, the lens will deform under the influence of the temperature gradient (the solid line shape in the figure changes to the dashed line shape). The resulting deformation affects the radius of curvature of the front and back surfaces of the lens, and the change in the radius of curvature of the lens causes a change in the focal length of the lens.
[0072] Based on the above principles, this invention designs a focal length microcontroller 13 capable of precisely controlling the focal length of a lens. The basic structure of the system is as follows: Figure 3 As shown.
[0073] like Figure 3 As shown, the system mainly consists of two sets of thermally conductive copper sheets 131 and 133, two sets of thermistors 134 and 135, one TEC 132, one microlens array 136, and one controller 2.
[0074] The TEC132 has a hollow, thin cylindrical structure, with the hollow portion having a square planar shape. The left side of the TEC132 is the hot side, and the right side is the cold side.
[0075] The microlens array 136 is a 10*10 microlens array arrangement, with the array size being the same as the hollow portion of TEC132. The microlens array 136 is embedded in the hollow portion of TEC132. The convex surface is located on the left side, and the flat surface is located on the right side. The microlens array 136 and TEC132 are fixed together with UV adhesive.
[0076] The thermal conductive sheets 131 and 133 are 0.5mm thick copper discs, and the square part in the middle is a grid made of copper wires with a diameter of 0.3mm. In this invention, the thermal conductive sheet 131 is located on the left side of the TEC and the microlens array, and is in close contact with the hot surface of the TEC. The copper wire grid in the middle is in close contact with the adjacent microlens spacer groove. The thermal conductive sheet 131 and the TEC 132 are fixed together by indium solder.
[0077] Thermistor 134 is located on the thermal conductive plate 131 and is fixed to the thermal conductive plate 131 by indium solder.
[0078] The thermal conductive plate 133 is located to the right of TEC132 and microlens array 136, and is in close contact with the cold surface of TEC132. The copper wire mesh in the middle is in close contact with the adjacent microlens spacer groove. The thermal conductive plate 133 and TEC132 are fixed together by indium solder.
[0079] Thermistor 135 is located on the thermal conductive plate 133 and is fixed to the thermal conductive plate 133 by indium solder.
[0080] The structure assembled according to the above positions is as follows: Figure 4 As shown.
[0081] The square light spot, after being collimated and expanded by the beam expansion system, is incident on the microlens array. After being focused by the microlens array, it forms a focal array, which can act on human skin to achieve corresponding therapeutic effects.
[0082] When the focal length of the microlens array changes, the laser focus changes accordingly, and the depth of the laser's effect on the skin during treatment also changes.
[0083] When a forward current is applied to the TEC132, the TEC132 continuously transfers heat from the right side to the left side, causing the temperature on the right side to decrease and the temperature on the left side to increase. This creates a temperature difference between the left and right surfaces, the magnitude of which is determined by the magnitude of the applied current.
[0084] The function of the heat-conducting plate 131 is to conduct the heat from the left side of TEC132 to the curved surface (left side) of the microlens array 136. The copper wire mesh in it has good thermal conductivity and can conduct heat evenly to each microlens unit, so that the temperature of each point on the curved surface (left side) of the microlens array is consistent.
[0085] The function of the thermistor 134 is to measure the temperature of the curved surface (left side) of the microlens array and feed back the actual temperature of the curved surface (left side) of the microlens array to the controller in real time.
[0086] The function of the temperature-conducting plate 133 is to conduct the low temperature on the right side of TEC132 to the plane (right side) of the microlens array. The copper wire mesh in it has good thermal conductivity and can conduct the temperature evenly to each microlens unit, so that the temperature of each point on the plane (right side) of the microlens array is consistent.
[0087] The function of the thermistor 135 is to measure the temperature of the microlens array plane (right side) and feed back the actual temperature of the microlens array plane (right side) to the controller in real time.
[0088] The function of controller 2 is to calculate the temperature difference between the left and right surfaces in real time, and then compare the calculation result with the set value. If it is greater than the set value, the current supplied to TEC132 will be reduced. If it is less than the set value, the current supplied to TEC132 will be increased. Through such cyclic control, the temperature difference between the front and rear surfaces of the microlens array is kept at the set value, thereby controlling the focal length of the microlens array to a preset value.
[0089] Taking the microlens array designed in this invention as an example, thermal stress analysis was performed on the lens under different front and rear surface temperature differences using the finite element method. The changes in the radius of curvature of the front and rear surfaces under different front and rear surface temperature differences are shown in Table 1.
[0090] Table 1. Surface curvature and focal length corresponding to different surface temperature differences.
[0091] Temperature difference / ℃ ΔR1 / mm ΔR2 / mm f / mm 0 0 0 7.8262572 1 0.0174787 0.0021437 7.8895469 2 0.0319649 0.0072746 7.9417444 3 0.0464583 0.0123925 7.9941521 4 0.060959 0.017497 8.0467709 5 0.0754668 0.0225879 8.0996018 6 0.0899816 0.0276649 8.1526457 7 0.1045034 0.0327277 8.2059035 8 0.119032 0.037776 8.2593761 9 0.1335674 0.0428096 8.3130644 10 0.1481094 0.0478281 8.3669695 11 0.162658 0.0528314 8.4210923 12 0.177213 0.057819 8.4754338 13 0.1917744 0.0627908 8.5299948 14 0.2063421 0.0677464 8.5847765 15 0.220916 0.0726855 8.6397797 16 0.235496 0.077608 8.6950055 17 0.250082 0.0825135 8.750455 18 0.2646739 0.0874016 8.806129 19 0.2792716 0.0922722 8.8620286 20 0.293875 0.097125 8.9181549
[0092] Further measurements were taken of the epidermal depth at multiple sites on the human body, and the results are shown in Table 2.
[0093] Table 2. Epidermal thickness at different parts of the human body
[0094] Part Average thickness / mm Forehead 1.40 upper eyelid 0.49 cheek 1.41 upper lip 1.25 lower lip 1.30 neck 1.38 front of the neck 0.90 Inner side of upper arm 0.91 outer side of upper arm 1.14 upper chest 1.29 abdomen 1.46 back 2.27 hips 1.99 Inner thigh 0.83 Inner thigh 1.00 outer thigh 1.32 Front of thigh 1.33 hamstrings 1.19 Back of the calf 1.00
[0095] Based on the data in Tables 1 and 2, it can be concluded that when the product of this invention is actually applied to a laser in medical aesthetics, fine-tuning of the focal length is required due to the different thicknesses of various parts. Therefore, the temperature difference between the front and back surfaces of the microlens array 136 should be controlled according to the corresponding relationship in Table 3 when treating various parts. Specific data are shown in Table 3.
[0096] Table 3. Temperature difference between the front and back surfaces of the microlens array and the corresponding TEC current for different skin locations.
[0097] Part Temperature difference / ℃ TEC current / A Forehead 25 5 upper eyelid 9 1.8 cheek 25 5 upper lip 23 4.6 lower lip 24 4.8 neck 25 5 front of the neck 17 3.4 Inner side of upper arm 17 3.4 outer side of upper arm 20 4 upper chest 24 4.8 abdomen 25 5 back 25 5 hips 25 5 Inner thigh 15 3 Inner thigh 18 3.6 outer thigh 24 4.8 Front of thigh 24 4.8 hamstrings 21 4.2 Back of the calf 18 3.6
[0098] Write the correspondence in Table 3 into controller 2, then adjust the focus to perform cosmetic treatments on different parts of the body.
[0099] When the user powers on the device, they select "Upper Eyelid" on the interface. The main control module then transmits the "Upper Eyelid" information to the controller of the focus micro-control module. The controller converts the "Upper Eyelid" information into "Temperature Difference 9℃", and further converts the "Temperature Difference 9℃" information into "TEC Input Current 1.8A", controlling the TEC to operate.
[0100] Simultaneously, thermistors 134 and 135 feed back the actual temperatures of the front and rear surfaces to controller 2. Controller 2 calculates the actual temperature difference between the front and rear surfaces and performs a logical comparison with the "temperature difference 9℃". If the "actual temperature difference" > "temperature difference 9℃", the control "TEC132 current 1.8A" is changed to "TEC132 current 1.7A", and the controller continues to receive new data from thermistors 134 and 135, calculate, compare, and control the TEC132 current. If the "actual temperature difference" < "temperature difference 9℃", the control "TEC132 current 1.8A" is changed to "TEC132 current 1.9A", and the controller continues to receive new data from thermistors 134 and 135, calculate, compare, and control the TEC132 current; this process is repeated cyclically.
[0101] In the above-mentioned cyclic control mode, the focal length of the microlens array 136 increases by 0.49mm, and the focal depth of the laser focal array after being focused by the microlens array 136 is 0.49mm below the skin, thus performing actual treatment on the upper eyelid.
[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A focal length adjustable laser, characterized by: It includes a laser module (1) and a control module (2) electrically connected to the laser module (1); The laser module (1) generates a laser pulse train and outputs it after shaping, focusing, and focal length adjustment. The control module (2) controls the operation of the laser module (1). The laser module (1) includes a laser generation system (11), a spot shaping system (12), and a focal length micro-control system (13) arranged sequentially. The laser generation system (11) and the focal length micro-control system (13) are both electrically connected to the control module (2). The laser generation system (11) generates the laser pulse train. The spot shaping system (12) shapes the laser pulse train into a spot and outputs it. The focal length micro-control system (13) focuses the spot and adjusts the focal length under the control of the control module (2) before outputting it. The focal length micro-control system (13) adjusts the focal length by adjusting the temperature difference between the front and rear surfaces of the lens to control the radius of curvature and refractive index of the lens. The focal length microcontroller (13) includes a first thermal conductive sheet (131), a TEC (132), a second thermal conductive sheet (133) arranged in sequence, a first thermal sensor (134) disposed on the first thermal conductive sheet (131), a second thermal sensor (135) disposed on the second thermal conductive sheet (133), and a microlens array (136) embedded in the middle of the TEC (132). The TEC (132) has a hollow structure, and the microlens array (136) is embedded in the hollow structure. The first thermal conductive sheet (131) is in close contact with the front surface of the TEC (132), and the second thermal conductive sheet (133) is in close contact with the rear surface of the TEC (132). After receiving current, the TEC (132) transfers the temperature on one side to the other side to create a temperature difference between the two surfaces. The first heat-conducting sheet (131) conducts the heat from one side of the TEC (132) to the front side of the microlens array (136), and the second heat-conducting sheet (133) conducts the heat from the other side of the TEC (132) to the back side of the microlens array (136). The temperature difference between the front and back sides of the microlens array (136) causes changes in the radius of curvature and refractive index of the microlens array (136), thereby adjusting the focal length. The microlens array (136) includes at least two microlenses (1361) arranged in an array and a spacer groove (1362) formed by the curved surfaces of two adjacent microlenses (1361). The first thermal conductive sheet (131) includes a hollow first thermal conductive sheet body (1311) and a first thermal conductive mesh (1312) connected to the hollow part of the first thermal conductive sheet body (1311). The first thermal conductive sheet body (1311) is a hollow sheet structure. The first thermal conductive sheet body (1311) is in close contact with the front surface of the TEC (132) and is fixed by welding. The first thermal conductive mesh (1312) is in close contact with the front surface of the spacer groove (1362). The second thermal conductive sheet (133) includes a hollow second thermal conductive sheet body (1331) and a second thermal conductive mesh (1332) connected to the hollow part of the second thermal conductive sheet body (1331). The second thermal conductive sheet body (1331) is a hollow sheet structure. The second thermal conductive sheet body (1331) is attached to the rear surface of the TEC (132) and fixed by welding. The second thermal conductive mesh (1332) is attached to the rear surface of the spacer groove (1362). The first temperature-conducting sheet body (1311) and the second temperature-conducting sheet body (1331) respectively transfer the temperature of the TEC (132) to the first temperature-conducting grid (1312) and the second temperature-conducting grid (1332), and the first temperature-conducting grid (1312) and the second temperature-conducting grid (1332) transfer the temperature to the microlens (1361).
2. The focal length adjustable laser according to claim 1, characterized in that: The focal length microcontroller (13) further includes a controller that is electrically connected to the TEC (132), the first thermal sensor (134) and the second thermal sensor (135), and the controller is electrically connected to the control module (2); The controller adjusts the temperature difference between the two sides of the TEC (132) by controlling the current output to the TEC (132). The first thermistor (134) and the second thermistor (135) transmit the temperature measurement values of the first thermal conductive sheet (131) and the second thermal conductive sheet (133) to the controller, respectively. The controller sets the target value of the temperature difference between the front and back surfaces of the microlens array (136) according to the control parameters output by the control module (2). Then, the controller adjusts the current output to the TEC (132) after comparing the target value with the temperature measurement value, so that the temperature difference between the front and back surfaces of the microlens array (136) reaches and maintains the target value.
3. A focal length adjustable laser according to claim 1, characterized in that: Both the first thermal conductive sheet body (1311) and the second thermal conductive sheet body (1331) are copper discs with square hollow portions. The shape of the square hollow portions corresponds to the shape of the microlens array (136). The first thermal conductive mesh (1312) is a copper wire mesh interwoven in the hollow structure of the first thermal conductive sheet body (1311), and the second thermal conductive mesh (1332) is a copper wire mesh interwoven in the hollow structure of the second thermal conductive sheet body (1331). The first thermal conductive sheet body (1311) is fixed to the front surface of the TEC (132) by indium solder, the second thermal conductive sheet body (1331) is fixed to the rear surface of the TEC (132) by indium solder, the first thermal sensor (134) and the first thermal conductive sheet (131) are fixed to each other by indium solder, and the second thermal sensor (135) and the second thermal conductive sheet (133) are fixed to each other by indium solder.
4. A focal length adjustable laser according to claim 1, characterized in that: The microlenses (1361) are arranged in an array of n rows and m columns; The convex surface of the microlens (1361) faces the first thermal conductive sheet (131), and the concave surface faces the second thermal conductive sheet (133). The temperature of the side of the TEC (132) facing the first thermal conductive sheet (131) is higher than the temperature of the side facing the second thermal conductive sheet (133).
5. A focal length adjustable laser according to claim 1, characterized in that: The microlens (1361) and the TEC (132) are fixed together by adhesive.
6. A focal length adjustable laser according to claim 1, characterized in that: The method for adjusting the focus of a laser includes the following steps: S1. The control module (2) outputs control parameters to the focal length micro-control system (13), wherein the control parameters are the target area for laser output; S2. The focal length micro-control system (13) adjusts the curvature radius and refractive index of the lens according to the temperature difference between the front and rear surfaces of the lens based on the control parameters, and outputs the real-time temperature measurement value to the control module (2). S3. The control module (2) compares the temperature measurement value with the target value and adjusts the magnitude of the current output to the focal length micro-control system (13). Return to step S2 until the temperature measurement value matches the target value.
7. A focal length adjustable laser according to claim 6, characterized in that: In step S1, the control module (2) outputs the control parameters to the controller; In step S2, the controller converts the control parameters into a target temperature difference and outputs a current of a corresponding magnitude to the TEC (132) according to the target temperature difference. The target temperature difference corresponds to the thickness of the target area. The TEC (132) transfers the temperature on one side to the other side according to the current magnitude, so that a temperature difference is formed on both sides. The first heat-conducting sheet (131) conducts the heat on one side of the TEC (132) to the front side of the microlens array (136), and the second heat-conducting sheet (133) conducts the heat on the other side of the TEC (132) to the back side of the microlens array (136). The temperature difference between the front and back sides of the microlens array (136) causes the radius of curvature and refractive index of the microlens array (136) to change, thereby adjusting the focal length. The first thermal sensor (134) and the second thermal sensor (135) respectively output the temperature measurement values of the first temperature conductive sheet (131) and the second temperature conductive sheet (133) to the control module (2); In step S3, the target value is the temperature difference between the first temperature conductor (131) and the second temperature conductor (133). If the difference in the measured temperature values is greater than the target value, the control module (2) reduces the current output to the TEC (132). If the difference in the measured temperature values is less than the target value, the control module (2) increases the current output to the TEC (132).