Custom Precision Borosilicate Glass Lenses In High-temperature Industrial Sensors

Custom Precision Borosilicate Glass Lenses In High-temperature Industrial Sensors

Material:

• Core Composition: Engineered borosilicate glass, primarily composed of silica (SiO₂ ~80%) and boron trioxide (B₂O₃ ~13%), with additions of alkalis and aluminum oxide.

• Key Variants: Often Schott Borofloat® 33, Pyrex®-type, or equivalent high-performance borosilicate formulations chosen for specific thermal/chemical needs.

Key Properties:

• Exceptional Thermal Stability:

  • Low Coefficient of Thermal Expansion (CTE): Typically ~3.3 x 10⁻⁶/K, minimizing dimensional change and stress under rapid or extreme temperature fluctuations.

  • High Thermal Shock Resistance: Withstands sudden temperature changes (ΔT > 150°C) without cracking, critical for processes like furnace entry/exit or quenching.

• High Temperature Endurance: Maintains structural integrity and optical clarity continuously at temperatures often exceeding 450°C, with short-term peaks significantly higher.

• Chemical Durability: Highly resistant to water, acids, alkalis, and solvents, preventing corrosion or clouding in harsh industrial atmospheres.

• Optical Clarity & Transparency: High transmission across relevant wavelengths (often visible to near-IR) essential for accurate light signal transmission in sensors.

• Mechanical Rigidity & Hardness: Provides structural stability and resistance to abrasion or particulate impact.

• Precision Manufacturability: Can be custom-ground and polished to tight tolerances (surface figure, centration, thickness) for specific optical requirements.

Primary Function:

• High-Temperature Optical Transmission Window: Acts as a robust, clear barrier protecting sensitive internal sensor components (detectors, electronics, optics) from extreme heat, corrosive gases, dust, and pressure differentials.

• Precise Light Path Control: Ensures accurate transmission, focusing, or collimation of light signals (e.g., infrared radiation for pyrometry, laser beams for alignment, visible light for inspection) within the sensor system, unaffected by thermal distortion.

• Environmental Sealing: Forms a hermetic or near-hermetic seal crucial for maintaining sensor calibration and protecting internal electronics.

Critical Applications:

• Non-Contact Temperature Sensors (Pyrometers): Viewports and focusing lenses directly exposed to molten metals (steel, aluminum, glass), hot kilns, furnaces, reactors, and welding processes.

• Laser-Based Sensors: Windows and optics in laser distance sensors, displacement sensors, and level sensors used in hot environments like metal processing, glass manufacturing, and semiconductor fabrication.

• Process Monitoring & Control: Lenses in cameras and optical sensors for high-temperature industrial inspection (e.g., glass forming, metal casting, ceramic sintering, semiconductor wafer processing).

• Combustion Monitoring: Optics in flame scanners and combustion analyzers within boilers, gas turbines, and incinerators.

• Gas Analysis Sensors: Windows protecting optical cells in Tunable Diode Laser Absorption Spectroscopy (TDLAS) and other analyzers in hot, corrosive exhaust streams or process gases.

• Semiconductor Manufacturing: Optics in sensors for lithography, etching, and deposition tools requiring thermal stability and chemical purity.

Summary: Custom precision borosilicate glass lenses are vital components enabling reliable operation of industrial sensors in extreme heat and harsh environments. Their unique combination of ultra-low thermal expansion, high thermal shock resistance, chemical durability, and optical clarity allows them to function as robust, stable optical windows and precise light-guiding elements. By protecting sensitive internals and ensuring accurate signal transmission, these custom lenses are essential for critical process control, safety monitoring, and quality assurance in demanding industries like metals, glass, power generation, chemicals, and semiconductor manufacturing.