Fresnel lens fixing method

Abstract

The invention relates to the technical field of Fresnel lens fixing, in particular to a Fresnel lens fixing method, which comprises the following steps of: screening and preprocessing materials; precisely machining the corrugated structure of the lens; customized production of the narrow circuit board is carried out; manufacturing an acoustic coupling gasket; optimizing ultrasonic welding parameters; synchronously welding the three layers of structures; carrying out complete machine assembly and low-temperature integration; and carrying out comprehensive performance verification. According to the ultrasonic welding fixing method, the gas or liquid filling requirement is thoroughly avoided, permanent sealing is achieved through HDPE / PC gasket molecular-level fusion, and the leakage rate is stably controlled within 0.5 Pa / min; a welding structure is not provided with an auxiliary metal piece, the weight of the whole machine is lighter, and the vertical falling tolerance is higher; the ultrasonic welding period is only 1.7 seconds, compared with a traditional sealing process, the efficiency is higher, the light transmittance is always maintained to be 90% or above due to the fact that silica gel is not filled, the illumination uniformity is higher in cooperation with the narrow circuit board design, and the comprehensive service life is longer.

Description

Technical Field

[0001] The invention relates to the technical field of Fresnel lens fixing, in particular to a method for fixing a Fresnel lens. Background Art

[0002] A Fresnel lens is an optical element that focuses or diffuses light through Fresnel rings. Its cross-section has a sawtooth corrugated structure, which can significantly reduce thickness and weight while maintaining optical performance. It is widely used in lighting, sensing and projection fields.

[0003] Generally, traditional Fresnel lens fixing methods mainly rely on sealing after filling with inert gas, filling with liquid silicone, or adding waterproof baffles for reinforcement. This process requires injecting inert gas (such as nitrogen) into the closed cavity after assembly and welding to seal it, or injecting transparent silicone to fill the gap between the lens and the bulb, and then supplementing it with mechanical locking using an external metal baffle.

[0004] However, the airtightness of the inert gas sealing process is easily affected by thermal expansion and contraction. After long-term use, the gas leakage rate increases by 15% annually, causing the lens to oxidize and fog. Although liquid silicone can cushion vibrations, silicone will gradually turn yellow if it continues to work above 80 degrees Celsius, and the transmittance will decrease by 8%-12% each year. The high-temperature fluidity may cause the lens to shift. The waterproof baffle reinforcement requires additional assembly screws and metal components, which increases the production cost by 30%. The difference in the thermal expansion coefficient of the metal can easily cause structural cracking, and the breakage rate in the 1.5-meter drop test is as high as 25%.

[0005] Based on this, the present invention provides a method for fixing a Fresnel lens to solve the above-mentioned technical problems. Summary of the Invention

[0006] The object of the present invention is to provide a method for fixing a Fresnel lens to solve the problems raised by the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions: The present invention provides a method for fixing a Fresnel lens, comprising the following steps: S1. Material screening and pretreatment; S2. Precision machining of lens corrugated structure; S3. Customized production of narrow-body circuit boards; S4. Acoustic coupling gasket manufacturing; S5.Optimization of ultrasonic welding parameters; S6. Three-layer structure simultaneous welding; S7. Whole machine assembly and cryogenic integration; S8. Comprehensive performance verification.

[0008] Preferably, the implementation process of step S1 is: The Fresnel lens is made of HDPE material with a melting point of 120 to 140 degrees Celsius and a thickness of 1.2 mm within a tolerance of 0.1 mm. Its acoustic wave conduction properties are used to accurately feedback the welding status; The bulb is made of PC material with a melting point of 260 degrees Celsius and a wall thickness of 1.5 mm to provide high temperature support; The customized composite gasket is made of a blend of HDPE and PC with a hardness of Shore D 70 and a tolerance of 5 units to ensure compatibility with the dual-material welding interface.

[0009] Preferably, the implementation process of step S2 is: The Fresnel lens is injection-molded from HDPE material based on S1. The corrugation depth is set to 0.25 mm with an error of 0.05 mm and a corrugation density of 15 lines per centimeter to improve the infrared sensing sensitivity by more than 30%. The surface roughness Ra value is controlled within 0.8 microns to ensure a transmittance of more than 90%.

[0010] Preferably, the implementation process of step S3 is: Reduce circuit board width to 80% of market standards, for example, from 20 mm to 16 mm. By optimizing LED layout, the density is increased by 25% and the shaded area is reduced by 35%. A high-precision etching process is used to control the line width tolerance within 0.05 mm, and the impedance test is completed within 5 milliohms.

[0011] Preferably, the implementation process of step S4 is: The gasket acts as an energy conduction medium. The upper surface matches the S1 bulb curvature radius of 50 mm, and the lower surface fits the S2 lens plane. The critical thickness is 0.8 mm, with an error of 0.05 mm and a flatness tolerance within 0.02 mm. The micro-groove depth of 0.1 mm increases the molten contact area by 30%, providing structural protection for welding strength.

[0012] Preferably, the implementation process of step S5 is: The core parameters were determined through experiments: a. The frequency is 20 kHz with an error of 0.5 kHz, matching the HDPE resonance point of S1; b. Amplitude 35 μm. Amplitude below 30 μm results in non-melting, while amplitude above 45 μm damages the S2 corrugated structure. c. Pressure 300 to 400 N, if it is less than that, the energy loss will exceed 15%; d. Welding time is 1.2 seconds with an error of 0.2 seconds, covering the HDPE melting point window; e. Maintain pressure for 0.5 seconds to complete molecular chain reorganization.

[0013] Preferably, the implementation process of step S6 is: The PC bulb of S1, the composite gasket of S4, and the HDPE lens of S2 are stacked in order. The ultrasonic welding head applies vertical pressure and focuses on the gasket lens interface. The real-time monitoring of the acoustic wave impedance change does not exceed 5%; The HDPE component of the gasket melts to form molecular entanglement, and the PC bubble shell of S1 maintains its shape due to its high melting point of 260 degrees Celsius. The welding peak temperature of 138 degrees Celsius accurately matches the melting point of S1's HDPE but is much lower than the melting point of PC, achieving selective fusion.

[0014] Preferably, the implementation process of step S7 is: Secure the lamp holder to the bulb base with a torque of 0.8 to 1.0 Nm; The narrow-body circuit board of S3 is embedded in the lamp cup, and the pins are connected using low-temperature reflow soldering with a peak temperature of 245 degrees Celsius, which is lower than the melting point of 260 degrees Celsius of the PC of S1; The helium mass spectrometer detects a leak rate of no more than 0.5 Pa per minute.

[0015] Preferably, the implementation process of step S8 is: Perform a 1.5-meter vertical drop test three times, and verify the S6 welding strength within 0.1 mm lens displacement; After aging for 1000 hours at 85 degrees Celsius and 85% humidity, the weld shear strength retention rate exceeded 95%, verifying the stability of the S5 parameters. The illuminance of the light efficiency test increased by 18% to 22%, integrating the S2 lens transmittance and S3 circuit board shading optimization results to form a closed-loop verification of the entire process.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The ultrasonic welding fixation method of the present invention completely eliminates the need for gas or liquid filling, and achieves permanent sealing through molecular-level fusion of HDPE / PC gaskets, with the leakage rate stably controlled within 0.5 Pa / minute; the welding structure has no auxiliary metal parts, the overall weight of the machine is lighter, and the vertical drop tolerance is higher; the ultrasonic welding cycle is only 1.7 seconds, which is more efficient than traditional sealing processes, and the light transmittance is always maintained above 90% due to the lack of silicone filling. Combined with the narrow circuit board design, the illumination uniformity is higher and the overall life is longer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of the method for fixing the Fresnel lens of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0019] See also Figure 1 The present invention provides a method for fixing a Fresnel lens, comprising the following steps: S1. Material screening and pretreatment; S2. Precision machining of lens corrugated structure; S3. Customized production of narrow-body circuit boards; S4. Acoustic coupling gasket manufacturing; S5.Optimization of ultrasonic welding parameters; S6. Three-layer structure simultaneous welding; S7. Whole machine assembly and cryogenic integration; S8. Comprehensive performance verification.

[0020] It should be noted that the implementation process of step S1 is as follows: The Fresnel lens is made of HDPE material with a melting point of 120 to 140 degrees Celsius and a thickness of 1.2 mm within a tolerance of 0.1 mm. Its acoustic wave conduction properties are used to accurately feedback the welding status; The bulb is made of PC material with a melting point of 260 degrees Celsius and a wall thickness of 1.5 mm to provide high temperature support; The customized composite gasket is made of a blend of HDPE and PC with a hardness of Shore D 70 and a tolerance of 5 units to ensure compatibility with the dual-material welding interface.

[0021] It should be noted that the implementation process of step S2 is as follows: The Fresnel lens is injection-molded from HDPE material based on S1. The corrugation depth is set to 0.25 mm with an error of 0.05 mm and a corrugation density of 15 lines per centimeter to improve the infrared sensing sensitivity by more than 30%. The surface roughness Ra value is controlled within 0.8 microns to ensure a transmittance of more than 90%.

[0022] It should be noted that the implementation process of step S3 is as follows: Reduce circuit board width to 80% of market standards, for example, from 20 mm to 16 mm. By optimizing LED layout, the density is increased by 25% and the shaded area is reduced by 35%. A high-precision etching process is used to control the line width tolerance within 0.05 mm, and the impedance test is completed within 5 milliohms.

[0023] It should be noted that the implementation process of step S4 is as follows: The gasket acts as an energy conduction medium. The upper surface matches the S1 bulb curvature radius of 50 mm, and the lower surface fits the S2 lens plane. The critical thickness is 0.8 mm, with an error of 0.05 mm and a flatness tolerance within 0.02 mm. The micro-groove depth of 0.1 mm increases the molten contact area by 30%, providing structural protection for welding strength.

[0024] It should be noted that the implementation process of step S5 is as follows: The core parameters were determined through experiments: a. The frequency is 20 kHz with an error of 0.5 kHz, matching the HDPE resonance point of S1; b. Amplitude 35 μm. Amplitude below 30 μm results in non-melting, while amplitude above 45 μm damages the S2 corrugated structure. c. Pressure 300 to 400 N, if it is less than that, the energy loss will exceed 15%; d. Welding time is 1.2 seconds with an error of 0.2 seconds, covering the HDPE melting point window; e. Maintain pressure for 0.5 seconds to complete molecular chain reorganization.

[0025] It should be noted that the implementation process of step S6 is as follows: The PC bulb of S1, the composite gasket of S4, and the HDPE lens of S2 are stacked in order. The ultrasonic welding head applies vertical pressure and focuses on the gasket lens interface. The real-time monitoring of the acoustic wave impedance change does not exceed 5%; The HDPE component of the gasket melts to form molecular entanglement, and the PC bubble shell of S1 maintains its shape due to its high melting point of 260 degrees Celsius. The welding peak temperature of 138 degrees Celsius accurately matches the melting point of S1's HDPE but is much lower than the melting point of PC, achieving selective fusion.

[0026] It should be noted that the implementation process of step S7 is as follows: Secure the lamp holder to the bulb base with a torque of 0.8 to 1.0 Nm; The narrow-body circuit board of S3 is embedded in the lamp cup, and the pins are connected using low-temperature reflow soldering with a peak temperature of 245 degrees Celsius, which is lower than the melting point of 260 degrees Celsius of the PC of S1; The helium mass spectrometer detects a leak rate of no more than 0.5 Pa per minute.

[0027] It should be noted that the implementation process of step S8 is as follows: Perform a 1.5-meter vertical drop test three times, and verify the S6 welding strength within 0.1 mm lens displacement; After aging for 1000 hours at 85 degrees Celsius and 85% humidity, the weld shear strength retention rate exceeded 95%, verifying the stability of the S5 parameters. The illuminance of the light efficiency test increased by 18% to 22%, integrating the S2 lens transmittance and S3 circuit board shading optimization results to form a closed-loop verification of the entire process.

[0028] Example 1: In practical applications, the method for fixing the Fresnel lens specifically includes the following steps: S1. Material screening and pretreatment: The Fresnel lens is made of HDPE material with a melting point of 120 to 140 degrees Celsius and a thickness of 1.2 mm within a tolerance of 0.1 mm. Its acoustic wave conduction characteristics can accurately feedback the welding status; The bulb is made of PC material with a melting point of 260 degrees Celsius and a wall thickness of 1.5 mm to provide high temperature support; The custom composite gasket is made of a blend of HDPE and PC with a hardness of Shore D 70 and an error of 5 units to ensure compatibility with the dual-material welding interface; This step lays the foundation for subsequent welding. The HDPE lens avoids the risk of high-temperature failure, and the PC bubble shell maintains a rigid structure. S2. Precision machining of lens corrugated structure: The Fresnel lens is injection-molded from HDPE material based on the S1. The corrugation depth is set to 0.25 mm with an error of 0.05 mm and a corrugation density of 15 lines per centimeter to increase infrared sensing sensitivity by more than 30%. The surface roughness Ra value is controlled within 0.8 microns to ensure a transmittance of more than 90%. This step relies on the S1 material properties. The HDPE melt fluidity supports micron-level corrugation accuracy. S3. Customized production of narrow PCBs reduces PCB width to 80% of market standards, for example, from 20mm to 16mm. By optimizing LED layout, density is increased by 25%, and the shading area is reduced by 35%. High-precision etching technology is used to control the line width tolerance within 0.05 mm, and the impedance test is completed within 5 milliohms; This design improves the optical performance of the S2 lens, narrows the circuit board, reduces shadows by 40%, and ensures complete coverage of the lens sensing area; S4. Acoustic coupling gasket manufacturing: The gasket acts as an energy conduction medium. The upper surface matches the S1 bulb curvature radius of 50 mm, and the lower surface fits the S2 lens plane. The critical thickness is 0.8 mm, with an error of 0.05 mm and a flatness tolerance within 0.02 mm. The 0.1mm micro-groove depth design increases the molten contact area by 30%, providing structural protection for S5 welding strength; S5. Ultrasonic welding parameter optimization: The core parameters were determined through experimental design: frequency 20 kHz with an error of 0.5 kHz to match the HDPE resonance point of S1; The amplitude is 35 μm. If the amplitude is less than 30 μm, it will not melt. If the amplitude is greater than 45 μm, it will damage the S2 corrugated structure. The pressure is 300 to 400 Newtons. If it is less than 300 Newtons, the energy loss will exceed 15%; Welding time is 1.2 seconds with an error of 0.2 seconds, covering the HDPE melting point window; Maintain pressure for 0.5 seconds to complete molecular chain reorganization; This step is the core of the process. Parameter imbalance will directly lead to S6 welding failure. S6. Three-layer structure synchronous welding: The PC bulb of S1, the composite gasket of S4, and the HDPE lens of S2 are stacked in order. The ultrasonic welding head applies vertical pressure and focuses on the gasket lens interface. The real-time monitoring of the acoustic wave impedance change does not exceed 5%; The HDPE component of the gasket melts to form molecular entanglements, while the PC bubble shell of S1 maintains its shape due to its high melting point of 260 degrees Celsius. The peak welding temperature of 138 degrees Celsius precisely matches the melting point of S1's HDPE but is much lower than the melting point of PC, achieving selective fusion. S7. Whole machine assembly and cryogenic integration: Secure the lamp holder to the bulb base with a torque of 0.8 to 1.0 Nm; The narrow-body circuit board of S3 is embedded in the lamp cup, and the pins are connected using low-temperature reflow soldering with a peak temperature of 245 degrees Celsius, which is lower than the melting point of 260 degrees Celsius of the PC of S1; The leakage rate detected by helium mass spectrometer shall not exceed 0.5 Pa per minute; At this stage, the S3 circuit board narrowing design is relied upon to avoid lens interference, and the S4 gasket welding layer ensures airtightness; S8. Comprehensive performance verification: Perform a 1.5-meter vertical drop test three times, and verify the S6 welding strength within 0.1 mm lens displacement; After aging for 1000 hours at 85 degrees Celsius and 85% humidity, the weld shear strength retention rate exceeded 95%, verifying the stability of the S5 parameters. The illuminance of the light efficiency test increased by 18% to 22%, integrating the S2 lens transmittance and S3 circuit board shading optimization results to form a closed-loop verification of the entire process; Through steps S1 to S8, the HDPE melting point of 120 to 140 degrees Celsius in step S1 of the present invention limits the S5 welding temperature window to 138 degrees Celsius, determines the S6 selective fusion effect and is verified by the S8 aging test; Reducing the width of the S3 circuit board by 35% reduces the risk of shading during S7 assembly, contributing to an 18% to 22% increase in illumination in S8 light efficiency testing. Step S2: The lens corrugation depth tolerance is 0.05 mm, requiring the S4 washer flatness to be within 0.02 mm, ensuring that the S6 welding energy is evenly transmitted and fed back to the S8 drop test displacement within 0.1 mm; Step S5: The welding amplitude is 35 microns. Based on the acoustic characteristics of the material in S1, the deviation is within 5% after real-time acoustic impedance monitoring in S6, and the target shear strength of 18 MPa is finally achieved in S8. In summary, the present invention achieves reliable welding of HDPE Fresnel lens and PC bulb, solves the processing problem of low-melting-point materials by optimizing acoustic parameters, and bridges the interface differences with an innovative gasket structure, thus forming a closed loop of material screening, precision machining, energy control, and performance verification.

[0029] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0030] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for fixing a Fresnel lens, characterized in that: The following steps are involved: S1. Perform material screening and pretreatment; S2. Perform precision machining of lens corrugated structure; S3. Customized production of narrow-body circuit boards; S4. Manufacturing acoustic coupling gaskets; S5. Optimize ultrasonic welding parameters; S6. Perform three-layer structure simultaneous welding; S7. Perform whole machine assembly and cryogenic integration; S8. Perform comprehensive performance verification.

2. The method for fixing a Fresnel lens according to claim 1, wherein: The implementation process of step S1 is as follows: The Fresnel lens is made of HDPE material with a melting point of 120 to 140 degrees Celsius and a thickness of 1.2 mm within a tolerance of 0.1 mm. Its acoustic wave conduction properties are used to accurately feedback the welding status; The bulb is made of PC material with a melting point of 260 degrees Celsius and a wall thickness of 1.5 mm to provide high temperature support; The customized composite gasket is made of a blend of HDPE and PC with a hardness of Shore D 70 and a tolerance of 5 units to ensure compatibility with the dual-material welding interface.

3. The method for fixing a Fresnel lens according to claim 2, wherein: The implementation process of step S2 is as follows: The Fresnel lens is injection-molded from HDPE material based on S1. The corrugation depth is set to 0.25 mm with an error of 0.05 mm and a corrugation density of 15 lines per centimeter to improve the infrared sensing sensitivity by more than 30%. The surface roughness Ra value is controlled within 0.8 microns to ensure a transmittance of more than 90%.

4. The method for fixing a Fresnel lens according to claim 3, wherein: The implementation process of step S3 is as follows: Reduce circuit board width to 80% of market standards, for example, from 20 mm to 16 mm. By optimizing LED layout, the density is increased by 25% and the shaded area is reduced by 35%. A high-precision etching process is used to control the line width tolerance within 0.05 mm, and the impedance test is completed within 5 milliohms.

5. The method for fixing a Fresnel lens according to claim 4, wherein: The implementation process of step S4 is as follows: The gasket acts as an energy conduction medium. The upper surface matches the S1 bulb curvature radius of 50 mm, and the lower surface fits the S2 lens plane. The critical thickness is 0.8 mm, with an error of 0.05 mm and a flatness tolerance within 0.02 mm. The micro-groove depth of 0.1 mm increases the molten contact area by 30%, providing structural protection for welding strength.

6. The method for fixing a Fresnel lens according to claim 5, wherein: The implementation process of step S5 is as follows: The core parameters were determined through experiments: a. The frequency is 20 kHz with an error of 0.5 kHz, matching the HDPE resonance point of S1; b. Amplitude 35 μm. Amplitude below 30 μm results in non-melting, while amplitude above 45 μm damages the S2 corrugated structure. c. Pressure 300 to 400 N, if it is less than that, the energy loss will exceed 15%; d. Welding time is 1.2 seconds with an error of 0.2 seconds, covering the HDPE melting point window; e. Maintain pressure for 0.5 seconds to complete molecular chain reorganization.

7. The method for fixing a Fresnel lens according to claim 6, wherein: The implementation process of step S6 is as follows: The PC bulb of S1, the composite gasket of S4, and the HDPE lens of S2 are stacked in order. The ultrasonic welding head applies vertical pressure and focuses on the gasket lens interface. The real-time monitoring of the acoustic wave impedance change does not exceed 5%; The HDPE component of the gasket melts to form molecular entanglement, and the PC bubble shell of S1 maintains its shape due to its high melting point of 260 degrees Celsius. The welding peak temperature of 138 degrees Celsius accurately matches the melting point of S1's HDPE but is much lower than the melting point of PC, achieving selective fusion.

8. The method for fixing a Fresnel lens according to claim 7, wherein: The implementation process of step S7 is as follows: Secure the lamp holder to the bulb base with a torque of 0.8 to 1.0 Nm; The narrow-body circuit board of S3 is embedded in the lamp cup, and the pins are connected using low-temperature reflow soldering with a peak temperature of 245 degrees Celsius, which is lower than the melting point of 260 degrees Celsius of the PC of S1; The helium mass spectrometer detects a leak rate of no more than 0.5 Pa per minute.

9. The method for fixing a Fresnel lens according to claim 8, wherein: The implementation process of step S8 is as follows: Perform a 1.5-meter vertical drop test three times, and verify the S6 welding strength within 0.1 mm lens displacement; After aging for 1000 hours at 85 degrees Celsius and 85% humidity, the weld shear strength retention rate exceeded 95%, verifying the stability of the S5 parameters. The illuminance of the light efficiency test increased by 18% to 22%, integrating the S2 lens transmittance and S3 circuit board shading optimization results to form a closed-loop verification of the entire process.

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