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Sapphire Crystal, Window
Sapphire windows are used in some non-ornamental applications, including infrared optical components, such as in scientific instruments; high-durability windows; wristwatch crystals and movement bearings; and very thin electronic wafers, which are used as the insulating substrates of very special-purpose solid-state electronics (especially integrated circuits and GaN-based LEDs) due to saphire's remarkable hardness (third hardest mineral, right behind diamond and moissanite).
Features of Sapphire Crystal
1. High-hardness - abrasion resistance
2. Transparency - in the range from ultraviolet to infrared light (0.15 - 5.5 µm)
3. Chemical resistance and heat resistance - resist almost all kinds of
acid and alkaline, heat up to 2000 °C.
4. Suitable for the application of insulation property required.
Sapphire Crystal Property
Crystal structure: Hexagonal
Lattice: a=4.785Å, C=12.991Å
Density: 3.98 g/cm³
Transmission Range: 150-5500 nm
Melting Point: 2040 °C
Specific Heat: 0.418 W.s/g/K
Thermal Conductivity: 25.12 W/m/K
Thermal Shock Resistance: 790 W/m
Thermal Expansion Coefficient: 5.8 x 10E-6/K
dn/dT: 13 x 10E-6/K @633nm
Hardness: 9 Mohs
Refractive Index: 1.83 @0.26µm, 1.76 @0.63µm, 1.58 @5.57µm
Sapphire Crystal Applications
- UV and IR Optics
- Windows for High Temperature and Pressure, Corrosion Resistance, Abrasion Resistance
- Heat Sink and Thermocouplers; Semiconductor Wafer Carriers
- Electrical Insulators
- Thin Film Deposition
- Transparent Electronic Substrate
- Silicon on Sapphire Wafers; Superconductor Substrate
Sapphire Crystal Window Specifications
Diameter Tolerance(mm): +0.0/-0.2 (General), +0.0/-0.1 (High Precision)
Thickness Tolerance(mm): ±0.2 (General), ±0.05 (High Precision)
Clear Aperture: >75% (Small Size), >90% (Large Size)
Parallelism: 3 arcmin. (General), 10 arcsec. (High Precision)
Surface Quality: 80/50 (General), 40/20 (High Precision)
Flatness (per 25mm@633nm): λ(General), λ/4 (High Precision)
Bevel (face width x 450 0) <0.25mm
Coating: Uncoated, AR, HR, PR Coating
OptoCity offer Sapphire crystal for various applications according to customer's specifications and drawing.