Why is borosilicate glass an ideal substrate for glass lenses?
Publish Time: 2025-08-21
In modern optical systems, glass lenses serve as core components for critical functions such as imaging, focusing, spectrometry, and laser transmission. The material properties of these lenses directly determine the accuracy, stability, and lifespan of the entire system. Among numerous optical glass materials, borosilicate glass, due to its excellent overall performance, has become the preferred substrate for manufacturing high-quality glass lenses. It is widely used in microscopes, telescopes, camera lenses, laser equipment, medical instruments, and industrial inspection systems.1. Excellent Optical Performance: High Transmittance and Low DispersionOne of the core advantages of borosilicate glass is its excellent optical transmittance. In the visible light band, its transmittance can reach over 90%, and it even exhibits good transmittance in the near-ultraviolet and near-infrared regions, making it suitable for multi-band optical systems. This is crucial for applications requiring high brightness and low-loss transmission, such as photographic lenses, endoscopes, and spectrometers. Furthermore, borosilicate glass has a moderate refractive index and a low dispersion coefficient (Abbe number around 60), effectively reducing chromatic aberration and improving image clarity and color reproduction. In multi-element lens designs, it is often used as a positive lens material in combination with other high-refractive-index or high-dispersion materials to achieve aberration correction, ensuring distortion-free and purple-free image edges.2. Excellent Thermal Stability: Low Thermal Expansion CoefficientThe most notable physical property of borosilicate glass is its extremely low thermal expansion coefficient, which is much lower than that of ordinary soda-lime glass. This means that the material's dimensions change minimally with temperature fluctuations, making it less susceptible to deformation or stress caused by thermal expansion and contraction. This property is particularly important in precision optical systems. For example, in outdoor telescopes, vehicle-mounted cameras, or high-power laser systems, ambient temperatures can fluctuate drastically. Lens materials with high thermal expansion coefficients can cause focal shift, image blur, and even cracking. However, borosilicate glass lenses maintain stable geometry and optical performance over a wide temperature range of -40°C to +300°C, ensuring long-term reliable system operation.3. Excellent Mechanical Strength and DurabilityBorosilicate glass has high hardness and compressive strength, making its surface scratch-resistant and able to withstand moderate mechanical shock and vibration. During the processing, coating, installation, and use of optical components, this mechanical stability helps reduce the risk of breakage, improve yield, and increase service life. Furthermore, its smooth and dense surface facilitates high-quality optical polishing and coatings (such as antireflection coatings, reflective coatings, and optical filters), further enhancing optical performance and environmental adaptability.4. Excellent Chemical Stability and Weathering ResistanceBorosilicate glass exhibits strong corrosion resistance to water, acids, alkalis, and atmospheric environments, and is resistant to moisture, mold, and surface fogging. This ensures long-term stable optical performance in humid, salty, and industrially polluted environments, making it particularly suitable for demanding applications such as medical equipment, marine observation instruments, and industrial sensors.5. Mature Processing Technology and Cost AdvantagesBorosilicate glass boasts a mature production process and a wide range of raw material sources, enabling large-scale and stable supply. Its moderate melting temperature makes it easy to precision mold, cut, grind, and polish, making it suitable for mass production of customized lenses of various curvatures, thicknesses, and sizes. Compared to specialty optical glasses such as fluoride and chalcogenide glasses, it offers an excellent balance between performance and cost, offering an exceptionally high cost-performance ratio.In summary, borosilicate glass, with its high transmittance, low dispersion, low thermal expansion, high mechanical strength, and excellent chemical stability, is an ideal substrate for glass lens manufacturing. It not only meets the stringent requirements of modern optical systems for precision, stability, and durability, but also offers excellent processability and affordability, serving as a bridge between optical design and practical application.
