Optical Glass Windows
H-K9L (N-BK7 equiv.) / Optical Borosilicate Glass
H-K9L optical glass is the Chinese domestic equivalent of Schott N-BK7 — a premium borosilicate glass with excellent optical homogeneity and machinability. It offers outstanding cost-performance for visible and near-infrared applications. Ideal when UV performance is not required.
Specifications (H-K9L / N-BK7 equiv.)
| Parameter | Value |
|---|---|
| Material | H-K9L Borosilicate Optical Glass (≡ N-BK7) |
| Transmission Range | 350nm–2200nm |
| Refractive Index nd | 1.5168 @ 587nm |
| Abbe Number Vd | 64.17 |
| CTE | 7.1×10⁻⁶/°C |
| Diameter Range | Ø1mm–Ø600mm |
| Thickness Range | 0.5mm–100mm |
| Surface Quality | 60-40 / 40-20 / 20-10 |
| Parallelism | < 1' / < 30" available |
Coating Services
- Broadband AR Visible — Multi-layer MgF₂ or oxide; R < 0.5% avg over 400–700nm
- AR Near-IR — Optimized for 700–1100nm or 1300–1550nm bands
- V-Coat AR at 1064nm — R < 0.25% per surface
- Note: H-K9L / N-BK7 is not recommended for UV applications below 350nm — use UV fused silica (JGS1) for UV laser work
Typical Applications
Visible Imaging SystemsLaboratory InstrumentsCost-Effective Laser SystemsIndustrial InspectionResearch & Education