KF50 Vacuum Viewport — KF50 Sight Glass for High Vacuum
KF50 vacuum sight glass (ISO-KF50) for high-vacuum systems. Available in borosilicate, fused silica and sapphire. Compact, quick-install KF flange, optional AR coatings and custom sizes.
Description
KF50 Vacuum Sight Glass (KF50 Viewport) — Compact High-Vacuum Optical Port
KF-50 vacuum viewport for high-vacuum process observation, optical alignment and inspection. Materials: borosilicate, fused silica (quartz), sapphire and IR crystals — selectable by wavelength and bakeout requirements.
Key benefits
- KF50 flange — compatible with standard KF clamps, centering rings and O-rings for fast installation.
- High-vacuum sealing — Viton O-rings or metal gaskets for low leak rates and repeatable sealing.
- Material options — borosilicate, fused silica (deep-UV), sapphire (high T & mechanical strength), CaF₂, ZnSe for IR.
- Compact & modular — ideal for small chambers, diagnostic ports and laser/spectroscopy access.
Quick specs
Visible aperture: 50 mm · Outer Ø: 75 mm · Glass thickness: 5 mm · Typical materials: borosilicate/quartz/sapphire.
Technical specifications
| Product model | KF50 |
|---|---|
| Vacuum rating (typ.) | Leak rate: ~1×10⁻¹² Pa·m³/s (sealing option dependent) |
| Flange material | Stainless steel 304 (other grades available) |
| Glass / window materials | Borosilicate · Fused silica (quartz) · Sapphire · BaF₂ · CaF₂ · ZnSe (choose by wavelength & temperature) |
| Surface quality & flatness | Surface quality: 60/40, 50/20, 20/10 · Optical figure: 1/2 → 1/10 (grade dependent) |
| Visible aperture (mm) | Ø 50 mm (standard; custom apertures available) |
| Outer / inner diameter | Outer Ø 75 mm · Inner Ø 50 mm |
| Product height & glass thickness | Product height 41.1 mm · Glass thickness 5 mm |
| Heat resistance (typ.) | ~150–230 °C (material dependent; sapphire/quartz can tolerate higher bakeout) |
Applications & industries
- Semiconductor equipment — plasma observation & process monitoring.
- Vacuum coating and thin-film deposition systems.
- Laboratory and R&D vacuum chambers.
- Laser alignment, spectroscopy and optical diagnostics in vacuum.
- Analytical instruments requiring optical access to high-vacuum environments.
FAQ — KF50 vacuum viewport
Which material for deep-UV transmission?
Fused silica (quartz) is the preferred choice for deep-UV (down to ~180 nm). Borosilicate is limited below ~300 nm; sapphire is mechanically robust but not ideal for the deepest UV.
Can I order custom diameters and higher flatness?
Yes — custom diameters, thicknesses, and optical grades (20/10, 1/10 wave flatness) are available. CAD drawings and small batch runs supported.
