Views: 0 Author: Site Editor Publish Time: 2025-10-21 Origin: Site
As the core optical component of an endoscope camera module, the lens's protective performance directly determines imaging stability and equipment service life. In scenarios pursuing miniaturization (e.g., lenses with a diameter of 1.5mm), adding a steel shell restricts spatial adaptability. Thus, a multi-dimensional protection system must be established through material upgrades, structural optimization, process control, and testing verification. Combining product characteristics and industry technical practices, this article analyzes the protection implementation path for steel-shell-free lenses.
The inherent performance of the lens substrate serves as the foundation for protection, requiring a balance between lightweight design and damage resistance. For the plastic lenses used in the product, medical-grade engineering plastics (such as modified PC or PEEK) are preferred. These materials not only enable miniaturized processing with a diameter ≤1.5mm but also withstand ethylene oxide sterilization in medical scenarios and chemical corrosion in industrial environments. To compensate for the insufficient hardness of plastics, surface enhancement technology is needed to improve wear resistance—vacuum coating can be used to deposit a 2-5μm thick diamond-like carbon (DLC) coating, raising the lens surface hardness to over HV1000 while maintaining an optical transmittance ≥92%, thus avoiding loss of imaging quality.
For temporary protection, high-quality polyethylene protective shells can be used. Their grid hole structure not only allows sterilization media to penetrate but also blocks sharp objects from scratching the lens during transportation and storage. Additionally, no residual adhesion remains after sterilization, meeting the sterility requirements of medical scenarios. This material system, combining "intrinsic substrate protection + surface enhancement + temporary physical barrier," can replace the mechanical protection function of a steel shell.
To achieve IP67-level dust and water resistance, steel-shell-free lenses rely on sealed structural design, with the core lying in interface sealing between the lens and module body, as well as between optical components. For the connection between the lens and lens holder, Elaplus SIPC 2150 neutral alcohol-free sealant can be used. This material maintains flexibility within a wide temperature range of -60℃~260℃, forming a dense sealing layer after curing. It can withstand immersion in 1.5 meters of water without leakage and produces no white fog volatile substances that might affect optical performance. The application of the sealant is precisely controlled by a dispensing robot, with the width limited to 0.2-0.3mm, ensuring effective sealing within the constraint of a 1.5mm diameter.
For the internal optical components of the lens, an integrated "pre-sealing + curing" solution can be adopted: after assembling the lens group via the Active Alignment (AA) process, ultraviolet (UV) curing adhesive is immediately injected into the gaps between components, followed by curing in a nitrogen-protected UV curing chamber. The oxygen-free environment prevents bubble formation during curing, increasing the sealing qualification rate from 88% to 99.5% while reducing curing time by 60%, ensuring consistency in mass production. Furthermore, a simple seal detection mechanism can be integrated—water-absorbent test paper and drainage grooves are installed at the lens tail to monitor water intrusion in real time and issue warnings.
Precision manufacturing processes are key to implementing protective performance. For lens injection molding, ultra-precision molds are used, with tolerances controlled within ±0.005mm to avoid sealing gaps caused by dimensional deviations. Before lens coating, ultrasonic cleaning with Class 10 cleanliness is required to remove particulate impurities larger than 0.1μm from the surface, ensuring the coating adheres properly.
During the module assembly stage, the Surface Mount Technology (SMT) process must be carried out in a Class 100 cleanroom to prevent contaminants such as solder dross from affecting the sealing effect. The assembly of the lens and sensor achieves μm-level alignment accuracy through the AA process, reducing the risk of sealant layer cracking caused by mechanical stress. Immediately after sealing, dual-channel airtightness testing is conducted, using positive pressure testing at 95-150kPa. Within 21 seconds (5 seconds for inflation + 10 seconds for pressure holding + 5 seconds for detection + 1 second for deflation), leaks in the range of -0.1~0.05kPa are accurately identified, ensuring the protective performance of each product meets standards.
The reliability of protective performance must be verified through multi-dimensional testing. Environmental adaptability testing includes 50 cycles of high-low temperature cycling (-40℃~80℃), with seal integrity and imaging clarity tested after each cycle. Corrosion resistance testing simulates medical sterilization processes—after 200 cycles of ethylene oxide sterilization, the lens transmittance attenuation is ≤3%.
In mechanical performance testing, a 1.5-meter drop test (dropping onto a hardwood surface) is repeated 10 times, with no structural damage to the lens observed afterward. For wear resistance testing, the lens surface is rubbed 1000 times with cotton cloth dipped in 75% alcohol, with no obvious scratches. All test data are synchronously stored in a database, and a traceability system is established in conjunction with certification requirements such as CE, FCC, and RoHS, ensuring the protective performance meets the strict standards of medical and industrial scenarios.
In summary, the protection of steel-shell-free lenses in endoscope camera modules requires "damage resistance of materials as the foundation, structural sealing as the core, process precision as the guarantee, and full-scenario testing as verification." Through the synergy of multiple technologies, compatibility between protection and miniaturization is achieved. This technical path not only meets the spatial requirements of ultra-fine 1.5mm lenses but also achieves IP67 protection level and long-term reliability, providing a feasible solution for scenarios such as minimally invasive medical procedures and industrial thin-pipe inspection.
