Cost-effective optical glass for visible-light applications
Borosilicate B270 is a cost-effective optical glass optimized for visible light applications (400–700 nm). It offers good transmission and homogeneity at lower cost than BK7. Commonly used for displays, simple lenses, filters, and applications where extreme optical precision is not required.
Borosilicate B270 is a crown glass offering good optical quality in the visible spectrum at an economical price point. It is widely used in applications where BK7-grade performance is not essential but better optical quality than float glass is needed.
B270 is particularly popular for display cover glass, simple lens elements, filter substrates, and general-purpose optical components in consumer and industrial applications.
Reference data — verify with PhotonEdge for project-specific specifications.
| Property | Value |
|---|---|
| Coefficient of Thermal Expansion (CTE) | 8.3 × 10⁻⁶ /K |
| Thermal Conductivity | 1.14 W/m·K |
| dn/dT (Thermo-optic Coefficient) | 3 × 10⁻⁶ /K |
| Maximum Operating Temperature | ~500°C (annealing point 525°C) |
Borosilicate glass (B270) has thermal properties similar to BK7 with slightly higher CTE. Suitable for general-purpose optics at moderate temperatures.
Broadband AR for 400-700nm. R < 0.5% per surface.
Typical use: Imaging and display applications
Substrate for visible-range mirror coatings.
Typical use: General-purpose mirrors
Raw glass surface acceptable for many display and filter applications.
Typical use: Display cover glass, filter substrates
Lower homogeneity than BK7. Not recommended for precision imaging or laser applications.
Transmission drops below 350nm. Not suitable for UV applications.
Significantly lower cost than BK7 for visible-only applications where premium optical quality is not needed.
Lower thermal resistance than BK7. Not suitable for high-power laser or extreme temperature applications.
Easy to machine, similar behavior to BK7. Standard optical fabrication methods apply.
Good polishability with conventional optical polishing techniques.
Good chemical resistance, stable in normal environments. Resists most common laboratory chemicals.
Low cost, widely available from multiple suppliers. Excellent value for general-purpose optics.
B270 is lower-cost but lower optical quality. BK7 for precision; B270 for cost-sensitive visible applications
B270 has better optical homogeneity and transmission than standard float glass
B270 is economy VIS-only; Fused Silica is premium UV-VIS-NIR
B270 is a borosilicate crown glass optimized for visible light applications. It offers good optical quality at lower cost than BK7.
Choose B270 when your application is visible-light only, cost-sensitive, and doesn't require the highest optical homogeneity.
Not recommended. B270 transmission drops significantly below 350nm. Use UV Fused Silica for UV applications.
Approximately 1.523 at 587.6 nm (sodium d-line).
For low-power visible laser alignment or display purposes, yes. For precision or high-power laser systems, BK7 or Fused Silica is recommended.
Describe your application and wavelength requirements. Our engineering team will recommend the optimal material grade and specifications.
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