BK7 Optical Glass: High-Performance Material for Precision Optics
BK7 optical glass is one of the most widely used materials in the optics industry. Known for its excellent clarity, high transmission, and good mechanical strength, BK7 is ideal for lenses, prisms, windows, and other precision optical components.
At [Your Company Name], we offer high-quality BK7 glass products that can be customized to your specifications, whether you need windows, lenses, or complex optical assemblies.
What Is BK7 Glass?
BK7 is a borosilicate crown glass produced by SCHOTT and other optical glass manufacturers. It is characterized by its:
- High optical quality
- Excellent transmission in the visible spectrum (350 nm – 2000 nm)
- Good mechanical durability and chemical stability
BK7 is typically used where cost-effective performance is required, especially in imaging systems, scientific instruments, and laser optics.
BK7 Optical Glass Composition
BK7 is a borosilicate-based glass with the following approximate composition:
| Component | Percentage (%) |
|---|---|
| SiO₂ (Silicon Dioxide) | ~70–72% |
| B₂O₃ (Boron Oxide) | ~10% |
| Na₂O/K₂O (Sodium/Potassium Oxide) | ~12–15% |
| Others (Al₂O₃, BaO) | Minor |
This composition ensures low bubble content, homogeneity, and high polishability—ideal for precision optics.
BK7 Refractive Index and Optical Properties
The refractive index of BK7 varies slightly with wavelength. At the standard wavelength of 587.6 nm (the “d-line”), its refractive index is:
- n₅₈₇.₆nm = 1.5168
Other key optical properties include:
| Property | Value |
|---|---|
| Refractive Index (n₅₈₇.₆nm) | 1.5168 |
| Abbe Number (Vd) | 64.17 |
| Density | 2.51 g/cm³ |
| Transmission Range | 350 nm to 2000 nm |
| Internal Transmission | >90% (for 10 mm thickness) |
BK7 Transmission Curve
BK7 offers excellent transmission in the visible and near-infrared regions.
(Insert suggestion: Graph showing BK7 transmission from 300 nm to 2200 nm)
- Transmission >92% in the 400–700 nm range
- UV transmission begins to drop below 350 nm
- Not recommended for deep UV applications (use UV fused silica instead)
BK7 Optical Windows
BK7 windows are used to isolate environments while maintaining optical clarity. They are commonly used in:
- Laser systems
- Cameras
- Environmental sensors
- Analytical instruments
We offer standard and custom BK7 optical windows with:
- Diameters from 5 mm to 200 mm
- Thicknesses from 0.5 mm to 25 mm
- Optional AR, HR, or custom coatings
(Insert suggestion: Image of a clear BK7 optical window)
Advantages of BK7 Optical Glass
- ✔️ High transmittance in visible and NIR
- ✔️ Easy to polish and coat
- ✔️ Excellent surface quality achievable (up to λ/10)
- ✔️ Cost-effective alternative to fused silica for visible light systems
BK7 Glass Applications
| Application Area | Example Uses |
|---|---|
| Laser Optics | Windows, lenses, beam splitters |
| Imaging Systems | Camera lenses, telescopes |
| Medical Devices | Optical assemblies, diagnostic tools |
| Laboratory Instruments | Spectrometers, microscopes |
| Industrial Systems | Protective windows, sensors |
BK7 Glass Price
The price of BK7 glass components depends on:
- Size and shape
- Surface quality
- Coating requirements
- Quantity ordered
Reference price range:
| Product Type | Price (USD) per piece |
|---|---|
| BK7 Window (25.4 mm Ø, uncoated) | $5 – $10 |
| BK7 Lens (50 mm focal length) | $15 – $30 |
| Custom BK7 Prism | $20 – $50+ |
Bulk orders and OEM pricing available on request.
BK7 vs Other Optical Materials
| Material | Refractive Index | UV Transmission | Cost |
|---|---|---|---|
| BK7 | 1.5168 | Fair (above 350 nm) | Low |
| Fused Silica | 1.458 | Excellent (down to 200 nm) | Medium |
| Sapphire | 1.76 | Good | High |
| CaF₂ | 1.43 | Excellent | Medium-High |
BK7 is ideal when UV performance is not critical and cost-effectiveness is a priority.
Custom BK7 Optical Components
We offer custom fabrication services for BK7 optics:
- Lenses (plano-convex, biconvex, meniscus)
- Prisms (right-angle, wedge, beam-splitting)
- Windows and mirrors
- High-precision polishing and AR coating
Let us know your required dimensions, tolerance, coating, and quantity, and we’ll quote within 24 hours.
Why Choose Bote Optics from Singapore?
- ✅ Experienced optical manufacturer
- ✅ Strict quality inspection (interferometry, surface quality, coating durability)
- ✅ Global shipping and fast delivery
- ✅ Support for prototyping and mass production
Contact Us for BK7 Glass Solutions
Looking for high-quality BK7 optical glass components?
Contact us today to get a fast quote, technical advice, or to discuss custom optical solutions for your project.