1. Why is sapphire glass irreplaceable in high-end applications

(1) Physical performance

With a heat resistance of 2045°C and a Mohs hardness of 9, it performs significantly better than standard optical glass in high-temperature, high-pressure, or highly abrasive scenarios.

(2) Optical purity

It boasts a 90% ultraviolet transmittance and an equivalent level of visible light transmittance, meeting the strict optical requirements of laser equipment, HUD displays and more.

(3) Chemical inertness advantage

Its resistance to acid and alkali corrosion far exceeds that of quartz glass, and its service life is extended by 3 to 5 times in the semiconductor etching process.

Sapphire glass substrates with irregular shapes are commonly used in scientific research. They precisely take advantage of these characteristics to ensure the accuracy of experimental data.

2. The classification and manufacturing process of sapphire glass

It can be classified into three categories according to the processing methods.

(1) Substrates: Sapphire glass substrates used for semiconductor substrates are characterized by surface roughness that is precisely controlled at the nanometre level.

(2) Irregular parts: Sapphire glass heat-bent parts formed by laser cutting or heat bending are suitable for special structural assembly.

(3) Optical components: The transmittance error of the double-sided polished lenses/windows is controlled within ±0.5%.

3. How to choose the most suitable sapphire glass based on the application scenario?

Sapphire glass cover plates: The 2mm-thick cover plate of the automotive HUD system must meet the requirements of both AR coating (reflectivity 94%) and AF anti-fingerprint treatment, with a Mohs hardness of 9, to ensure that it cannot be scratched for a period of ten years.

Sapphire glass lenses: In the instance of the focal length tolerance of the biconconcave lens being within ±2%, there is a necessity to select optical-grade materials of a refractive index of 1.76-1.77, whilst a fine grinding and polishing process must be matched.

4. Essential tools for sapphire glass processing and maintenance

(1) Precision cutting

When the thickness exceeds 1mm, a UV laser for the sapphire glass cutting machine is required, with a minimum line width of 100μm.

(2) Surface treatment

When the flatness requirement is less than 0.01mm, a double-sided sapphire glass polishing machine must be used, and the diameter of the star wheel should be selected as 430mm.

(3) Temporary protection

For transfer storage, low-adhesion PE protective film should be applied to prevent suction cup marks.

5. Common problems and solutions in the use of sapphire glass

Thermal stress cracking: Avoid sudden cooling from above 200℃ to room temperature. The cooling rate should be controlled at 5℃/min.

Surface contamination: Clean monthly with anhydrous ethanol and microfiber cloth. Do not use ammonia-containing cleaners.

Edge chipping: During the installation process, it is imperative to ensure a minimum distance of 3mm between the force-bearing point and the edge. If deemed necessary, a sapphire glass protective film can be applied.

Attenuation of optical performance: The light transmittance should be tested every two years. If it drops by more than 5%, the coating needs to be reapplied.

The selection of sapphire glass is fundamentally a matter of balancing performance redundancy and cost, with considerations including heat resistance temperature and light transmittance tolerance. For key components, it is recommended to reserve a 20% performance margin, especially for optical elements such as sapphire glass plates. In scenarios where the customization of intricate shapes is imperative, the surface subjected to the sapphire glass coating treatment can enhance its durability by a factor of three.