Borosilicate Windows
Borosilicate Optical Windows
A borosilicate window is a precision-polished optical plate designed for systems that require stable transmission and strong environmental durability. Engineers often select borosilicate not because it is exotic, but because it performs consistently under real operating conditions—temperature fluctuations, repeated cleaning cycles, outdoor exposure, and chemical contact. When long-term reliability matters more than theoretical optical perfection, borosilicate glass delivers dependable performance.
Borosilicate Materials Including SCHOTT BOROFLOAT® 33
We manufacture borosilicate windows using high-grade borosilicate crown glass, including SCHOTT BOROFLOAT® 33. This material is recognized for its high chemical purity, uniform refractive index, and extremely low thermal expansion.
BOROFLOAT® 33 is produced using a precision microfloat process, resulting in exceptional surface flatness and minimal internal defects. These characteristics make it particularly suitable for instrumentation, inspection optics, and applications where flatness uniformity directly impacts system performance.
Standard Manufacturing Tolerances and Optical Quality Control
Our factory standard borosilicate windows are manufactured with a clear aperture exceeding 85% of the total diameter. Diameter tolerance is controlled to +0.0 / –0.05 mm, while thickness tolerance is maintained at ±0.1 mm, ensuring predictable alignment and integration in optical assemblies.
Typical standard specifications include:
Material: Borosilicate glass (including SCHOTT BOROFLOAT® 33)
Surface flatness (Irregularity): λ/10
Surface quality: 20–10 scratch-dig
Parallelism: 1 arc minute
Wavefront distortion: λ/10 per 25 mm
Clear aperture: >85%
For applications with tighter requirements, enhanced tolerances and surface specifications are available upon request.
Coating Options and Edge Protection Features
Borosilicate windows can be supplied uncoated or with anti-reflection coatings. AR coatings are commonly optimized for the visible (VIS) or visible–near-infrared (VIS–NIR) spectral ranges, depending on system requirements.
Protective edge treatments, including safety bevels and chamfers, are available to improve handling safety and edge durability during installation and operation.
Standard Sizes and Custom Borosilicate Window Fabrication
Our standard inventory includes circular borosilicate windows with diameters ranging from 5 mm to 100 mm and thicknesses between 1 mm and 5 mm. Square, rectangular, and oversized BOROFLOAT® 33 windows can also be fabricated to order.
For high-temperature environments or chemically aggressive applications, we can further optimize surface flatness, thickness uniformity, or surface quality to meet system-specific demands.
Engineering Support and Production Capability
Our engineering team supports early-stage design reviews and material selection, helping customers identify the appropriate borosilicate specification based on mechanical, thermal, and optical constraints. With in-house grinding, polishing, and metrology capabilities, we ensure consistent quality from single prototypes through scaled production runs.
