Sapphire Windows

Sapphire Windows

Why people use sapphire windows?

Sapphire has excellent surface hardness. It is wear-resistant and scratch-resistant. Sapphire windows are thinner than optical components made of other optical materials with the same hardness. Sapphire is transparent in the vacuum ultraviolet to mid-infrared range. Due to its unique structure, the birefringence effect of transmitted light can be eliminated. Sapphire has stable chemical properties, high temperature resistance and long service life. It is often used in high pressure and harsh working environments. Sapphire is increasingly replacing quartz glass in optical applications.


What applications is sapphire used for?

According to different shapes, sapphire windows can be divided into circular sapphire windows, square sapphire windows and hemispherical sapphire windows (sapphire domes). In the medical optics, sapphire windows are often used in endoscopes, scalpels, laser surgery and light guide blocks for cosmetic instruments. In optical instruments, sapphire windows are commonly used in vacuum windows, infrared laser systems, spectrometers, interferometers and optical sensors. Sapphire windows are also used as watch faces, mobile phone screens, protect windows and fingerprint lock protectors. Sapphire domes are commonly used in fairings for infrared missiles and protective covers for underwater imaging and detection systems.


Application of Sapphire Window


The sapphire window can be installed as a sealing window on the outside of the lens of the endoscope to protect the optical lens and sensors for internal imaging. Sapphire is resistant to acid, alkali and high temperature, which ensures good air tightness. It possesses biocompatibility. As a protective window, sapphire windows effectively protect the endoscope from water vapor, tissue fluid, gastric acid, high temperature disinfection and other situation, which corrode the internal optical lens and sensors. Sapphire window ensure the clarity of the optical imaging, allowing the endoscope to be used repeatedly for a long time.


Sapphire smartphone screen

Sapphire has a Mohs scale of 9, while optical glass has a Mohs scale of 6. The fracture toughness value of sapphire is approximately three times that of other optical glasses. Therefore, sapphire mobile phone screens are more durable than mobile phone screens of other materials. The sapphire mobile phone screen is not easy to be scratched by foreign objects. It is not easy to be broken screen due to hitting and falling. In addition, sapphire has the ability to transmit light in the ultraviolet to infrared range, which not causes visual confusion and affects the imaging effect of pictures, videos and software.



Sapphire has good wear resistance and high glass hardness. Generally, scratches will not be rubbed, which affects the photo effect. Although the light transmission performance of sapphire windows is not as good as that of special glass for optical lenses, it is sufficient to meet the daily needs of mobile phone photography and video recording. Because of its high-quality surface hardness, sapphire windows effectively protect mobile phone lenses, camera lenses and photographic lenses, avoid damage to precise optical lenses. Sapphire windows ensure the image effect of imaging and photography.


Sapphire infrared window

As an infrared observation window, sapphire window is an internal observation window for high-voltage complete sets of electrical equipment. The working band of the infrared window is 0.15-12.5μm, which can transmit ultraviolet, visible light and infrared rays. The infrared working band range is 780nm-12.5μm. Before sapphire windows go into service, they (infrared observation window) needs to undergo high-voltage tests such as insulation, sealing, impact, temperature rise, and humidity.

The main testing instruments for high-voltage electrical equipment are infrared thermometers and infrared thermal imagers. Corona and internal discharge can also be visually detected with ultraviolet imagers. The high-voltage switch contacts and busbar connection points are in a closed environment, which cannot penetrate infrared, ultraviolet, and visible light. Therefore, traditional thermocouples, temperature probes, optical fibers and other instruments cannot achieve accurate temperature measurement. The infrared window is an optical window that transmits light. By installing the infrared window on the switch cabinet, the temperature measurement through infrared imaging can be realized when the switch cabinet is in operation.

Due to the feature of sapphire, sapphire infrared observation window has the advantages of infrared penetration, electrical insulation, corrosion resistance, and intrinsic safety. It is suitable for installation on high-voltage switchgear, realizes temperature measurement of switchgear through infrared imaging, and solves the hidden danger of overheating of high-voltage switchgear contacts. The crystal material of the infrared observation window has a high light transmittance. It is mainly used in medium and high voltage electrical equipment, as well as in all closed places that require temperature measurement.


Sapphire domes & Sapphire fairings

The optical properties of sapphire meet the requirements of the optical system to form a clear image. The sapphire dome or sapphire fairing has a high surface hardness, high impact toughness, good chemical stability and high mechanical strength. At the same time, the sapphire dome or sapphire fairing has high temperature stability. They can withstand the high temperatures formed by aerodynamic heating during flight. Therefore, the sapphire dome or sapphire fairing ensures the optical performance of the photoelectric sensor to ensure its infrared imaging quality when subjected to thermal shock, wind and sand, rain and snow, salt solution or corrosive gas in the atmosphere and underwater environment. It can also protect the infrared sensor and its photoelectric device from being damaged by the external environment. Sapphire dome or sapphire fairing meets the requirements of infrared detection, infrared guidance and underwater robot detection.



Sapphire windows have good transmittance in the ultraviolet, visible and infrared ranges. At the same time, sapphire windows have excellent hardness. As a result, sapphire windows improve the performance of barcode scanners, QR code scanners and other scanners. It not only avoids the damage of scanners, but also maintains the accuracy of scanning.

CLZ Optical Co., Ltd.  supply a range of quality Sapphire windows, including custom laser windows, custom sapphire windows and Sapphire blanks and provide specialty coatings such as BBAR, short or long pass, V or W coating.