Material Grades for Sapphire
Material grades are indicative of the suitability of the sapphire material for polishing and optical applications. Rubicon’s quality control staff screens for all inclusions and bubbles.
Method for Material Inspection
Inclusions, bubbles, and concentrations of micro-bubbles within the sapphire material are assessed by visual inspection under high-intensity light. A “micro-bubble” is defined as a bubble that is too small to be individually discernible by visual inspection under high-intensity light (more exactly, a bubble with less than a 15-micron diameter). Lineage, twins, and grain boundaries are assessed by visual inspection under polarized light.
Optical Grade Sapphire
Material Inclusions, lineage, twins, and macro-bubbles are not permitted.
Bubbles no larger than 50 microns in diameter and no closer in distance than 500 microns are permitted.
Micro-bubbles (bubbles up to 15 microns in diameter) are permitted.
Micro-bubble concentrations not visible by an unaided eye are permitted in areas no larger than 20 mm in diameter.
Laser Grade Sapphire
Micro-bubbles larger than 15 microns in diameter and not closer in distance than 500 microns are not permitted. (Bubbles less than 15 microns are generally not visible to the naked eye).
All other bubble types are not permitted.
Inclusions, lineage and twins are not permitted.
UV Grade Sapphire
Rubicon Technology defines general UV Grade sapphire to be material that is non-browning under exposure to 254 nm wavelength light.
Specific transmission properties of UV Grade sapphire depend heavily upon wavelength, intensity, and cumulative exposure time.
Any UV transmission requirements should be noted on all inquiries.
Mechanical Grade Sapphire
Bubbles and micro-bubble concentrations not larger than 500 microns in diameter are permitted. Inclusions, twins, and lineage are permitted.
All types of defects, other than cracks, are permitted.
Variety of mechanical grade options available upon request.
