Views: 0 Author: Site Editor Publish Time: 2025-11-24 Origin: Site
In endoscopic camera modules, lens material is a core factor determining imaging quality, durability, and cost. From a popular science perspective, this article systematically analyzes the key impacts of three materials—plastic, glass-plastic hybrid, and all-glass—on endoscopic modules, helping to understand the material selection logic for different application scenarios.
Plastic lenses are mainly made of optical-grade plastics such as PMMA (polymethyl methacrylate) and PC (polycarbonate). Their core advantage lies in processing convenience and cost control. Plastics can be mass-produced into complex curved surfaces through injection molding, which can quickly adapt to the miniaturization and lightweight design requirements of endoscopic modules, especially suitable for micro-endoscopic lenses with a diameter of less than 3mm.
Limited Optical Performance: The light transmittance of plastics is usually 85%-90% (lower than that of glass, which is over 95%), and their refractive index is relatively low (1.49-1.59). They are prone to optical defects such as dispersion and distortion, resulting in insufficient imaging resolution and contrast of the module, which makes it difficult to meet high-precision detection requirements;
Weak Environmental Adaptability: Plastics have poor thermal stability (with a heat resistance temperature mostly between 80-120℃). In scenarios such as high-temperature sterilization of medical endoscopes (e.g., 134℃ high-pressure steam sterilization) or industrial high-temperature detection, they are prone to deformation and aging, affecting the focal stability of the lens;
Insufficient Corrosion Resistance: They have poor tolerance to chemical reagents commonly used in medical disinfection, such as alcohol and hydrogen peroxide. Long-term use may lead to surface cracking and decreased light transmittance, shortening the service life of the module.
Therefore, plastic lens modules are mainly used in entry-level medical endoscopes, simple industrial testing equipment, and other scenarios with low requirements for imaging accuracy and mild operating environments.
Upgraded Optical Performance: Core imaging lenses (such as objective lenses and field lenses) use high-transmittance glass (e.g., quartz glass, optical glass), which can increase the light transmittance of the module to over 92%, effectively suppressing dispersion and glare. At the same time, plastic lenses can optimize the lens curvature design, reduce the number of lenses, and achieve a balance between module miniaturization and high resolution;
Improved Environmental Adaptability: The heat resistance (up to over 200℃) and chemical corrosion resistance of glass lenses enable the module to adapt to routine medical disinfection processes. The toughness of plastic lenses can reduce the overall brittleness of the lens and improve the module's anti-drop and anti-vibration capabilities;
Controllable Cost: Compared with all-glass lenses, the glass-plastic hybrid solution reduces the usage of high-precision glass lenses, lowering processing costs by 30%-50%. At the same time, it avoids the performance shortcomings of pure plastic lenses, showing significant cost-effectiveness advantages.
Glass-plastic hybrid lens modules are widely used in routine medical diagnostic endoscopes (e.g., gastroscopes, colonoscopes), precision industrial non-destructive testing equipment, and other scenarios that require a balance between performance and economy, making them the preferred solution for such applications.
Peak Optical Performance: The light transmittance of optical glass can reach 95%-99%, with a wide refractive index range (1.5-1.9). It can accurately correct optical aberrations such as spherical aberration and chromatic aberration. Combined with high-precision grinding technology, it can achieve micron-level imaging resolution, meeting the strict requirements for detail recognition in minimally invasive surgery, high-end industrial testing, and other scenarios;
Tolerance to Extreme Environments: Glass materials generally have a heat resistance temperature of over 200℃, enabling them to withstand extreme environments such as medical high-pressure steam sterilization and industrial high-temperature testing. They also have strong tolerance to chemical disinfectants, industrial oil stains, etc. The optical performance decays slowly after long-term use, and the service life of the module can reach 5-10 years (far longer than the 1-2 years of plastic lenses);
Excellent Stability: Glass has a low thermal expansion coefficient. In scenarios with drastic temperature changes (e.g., moving from room temperature to the human body or an industrial furnace), its focal stability is better than that of plastic and glass-plastic hybrid lenses, avoiding blurred imaging caused by thermal deformation.
However, all-glass lenses also have obvious disadvantages: glass processing is difficult and costly (5-10 times that of plastic lenses), and the lenses are relatively heavy, which places higher requirements on the lightweight design of the module. Therefore, they are mainly used in high-end medical minimally invasive surgery endoscopes, aerospace precision testing equipment, and other scenarios with extreme performance requirements.
Optical Performance: Medium level, with light transmittance of 85%-90% and refractive index of 1.49-1.59; prone to dispersion and distortion, with limited resolution and contrast;
Durability: Weak, with a heat resistance temperature of 80-120℃; incompatible with high-temperature sterilization; poor tolerance to chemical reagents such as alcohol and hydrogen peroxide; prone to aging and cracking after long-term use; service life of 1-2 years;
Cost Level: Low, with processing costs only 1/5-1/10 of all-glass lenses, suitable for mass production;
Core Application Scenarios: Entry-level medical endoscopes, simple industrial testing equipment, and other scenarios with low requirements for imaging accuracy and mild operating environments.
Optical Performance: High level, with light transmittance ≥92%; core imaging lenses (glass material) suppress dispersion and glare; plastic lenses optimize curvature design, balancing high resolution and miniaturization;
Durability: Medium, with glass lenses having heat resistance ≥200℃ and chemical corrosion resistance, compatible with routine medical disinfection; plastic lenses enhance overall toughness, with better anti-drop and anti-vibration capabilities than all-glass lenses;
Cost Level: Medium, with costs 30%-50% lower than all-glass lenses, showing prominent cost-effectiveness;
Core Application Scenarios: Routine medical diagnostic endoscopes (e.g., gastroscopes, colonoscopes), precision industrial non-destructive testing equipment, and other scenarios that require a balance between performance and economy.
Optical Performance: Ultimate level, with light transmittance of 95%-99% and refractive index of 1.5-1.9; accurately corrects spherical aberration and chromatic aberration; achieves micron-level imaging resolution with low distortion;
Durability: Extremely strong, with heat resistance temperature ≥200℃; can withstand high-pressure steam sterilization and industrial high-temperature environments; highly resistant to chemical corrosion and oil stains; slow optical performance decay; service life of 5-10 years;
Cost Level: High, with difficult processing and costs 5-10 times that of plastic lenses;
Core Application Scenarios: High-end medical minimally invasive surgery endoscopes, aerospace precision testing equipment, and other scenarios with extreme performance requirements.
With the maturity of molded glass and wafer-level glass (WLG) technologies, glass-plastic hybrid lenses are becoming the mainstream solution for endoscopes. By using glass lenses to undertake core refractive tasks and plastic lenses to achieve complex surface correction, they not only avoid the temperature drift defect of pure plastic lenses but also overcome the high cost and weight issues of all-glass lenses. In the future, nanocoating technology will further improve the wear resistance and light transmittance of plastic lenses, while the development of degradable bioplastics may reshape the ecosystem of disposable endoscopes.
As the "imaging cornerstone" of endoscopic camera modules, the selection of lens material is essentially a comprehensive trade-off between performance, cost, and application scenarios. Plastic materials meet basic needs, glass-plastic hybrid materials achieve a balance between performance and cost, and all-glass materials pursue ultimate performance. With the development of material technology, more lightweight and environment-resistant new optical materials may emerge in the future, further promoting the upgrading of endoscopic camera modules toward higher precision, miniaturization, and longer service life.
