Reticles
Material
| Substrate material | selected float glass, BK7 optical glass, ceramics, aluminium oxide and others. Low CTE: quartz glass, borosilicate, Robax, Zerodur. |
| Thickness of substrate | 0,5 - 8 mm |
|
Coating - optical density - reflection - layer thickness |
vacuum deposited chrome 1.5 - 3 (±5%) at 400-900 nm < 60% at 400-900 nm 200÷4000 Å |
|
Shape of reticle |
any |
|
Reticle processing |
scribed and broken, laser cutting, grinding |
| Outbreaks on edges | < 0.1 mm |
| Grinded, polished glass | edges parallelism 0.015 mm/m |
Pattern
| Coating | Aluminum, silica, chrome, anti-reflective chrome and others on request |
| Mark period ratio deviation | ±2.5% |
| Max. graduation accuracy | 2 arc. sec |
| Graduation coaxiality to outside diameter | < 0.1 mm |
| Grating pitch | from 8 μm |
