Fused Silica Optics Co.,LTD
Fused Silica Optics Co.,Ltd
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67mm Best Variable Neutral Density Optical Filter for Digital Camera
Absorption and particularly wavelength selective absorption is an important factor in the function of the filters. The two most commonly used absorbers are thin metallic films which are particularly insensitive to wavelength for absorption and colored glasses which absorb wavelengths varied by as much as several orders of magnitudes in only tens of nanometers. Interference filters are multilayer dielectric thin film devices. Metallic films, colored glasses and thin dielectric films are used in Fused Silica Optics filters.
ND filters include absorptive and reflective filters,which are used in attenuating lasers and other optical signals. Absorptive filters minimize back reflections, which can be reduced further by adding an antireflection coating to the filter. reflective filters are available with either a BK7 or UV Fused Silica substrate.
Specification
| Substrate material | UV Grade Fused Silica or BK7 |
| Diameter | 25.0 +0~-.025 mm |
| Thickness | 3 ± 0.5 mm |
| Min. clear aperture | >85% of diameter |
| Transmission | >90% average within specified range |
| Attenuation | >99% average within specified range |
| Angle of incidence | 0° ± 5° |
| Coating Technology | Electron beam evaporation, dielectric multilayers |
| Surface quality | 40/20 per MIL-O-13830B |
| Wedge | <3 minutes |
| Wavefront distortion | ≤1λ @ 633nm per 25mm |
| Humidity resistance | Per MIL-C-675A |
| Abrasion resistance | Per MIL-C-675A |
| Optimum temperature | 23°C |
| Temperature limits | -50°C to 100°C |
| Certification | Spectrophotometer print of lot sample |
| Cleaning | Non-abrasive method, isopropyl alcohol on lens tissue recommended |
| Laser Induced Damage Threshold(LIDT) | >3J/cm2 (1.06μm, 1ns) |
| Surface quality | 20/10 per MIL-O-13830B |