What type of glass is BK7?

BK7 glass is a type of optical glass that is commonly used in a wide range of applications due to its excellent optical properties. It is known for its high transmission in the visible and near-infrared range, making it an ideal choice for lenses, prisms, and other optical components. Understanding the properties and characteristics of BK7 glass can help users make informed decisions when selecting materials for optical applications.

## What is BK7 glass?

BK7 glass is a borosilicate crown glass that is composed of boron trioxide, silica, and other additives. It belongs to the Schott glass catalog and is classified as a type of optical glass with specific properties that make it suitable for optical applications. BK7 glass is characterized by its high transparency, low absorption, and high refractive index, making it suitable for use in lenses, prisms, and windows in optical systems.

## Optical properties of BK7 glass.

One of the key properties of BK7 glass is its high transmission in the visible and near-infrared spectrum. This means that BK7 glass allows light to pass through with minimal absorption, making it ideal for applications where high optical throughput is required. In addition, BK7 glass has a high refractive index, which means that it bends light at a sharper angle compared to other types of glass with lower refractive indices.

Another important optical property of BK7 glass is its low dispersion, which means that it has minimal chromatic aberration. Chromatic aberration occurs when different wavelengths of light are focused at different distances, resulting in color fringing in images. By using BK7 glass with low dispersion, optical designers can minimize this effect and achieve sharper, clearer images.

## Mechanical properties of BK7 glass.

In addition to its optical properties, BK7 glass also exhibits good mechanical properties that make it suitable for use in optical applications. BK7 glass is relatively hard, with a Vickers hardness of around 400, making it resistant to scratching and abrasion. It also has good chemical resistance, allowing it to withstand exposure to harsh environments without degrading its optical performance.

One of the drawbacks of BK7 glass is its relatively low thermal expansion coefficient, which can lead to thermal stress in optical components when exposed to temperature fluctuations. To mitigate this issue, optical designers may need to consider using thermal management techniques or alternative materials with higher thermal stability for specific applications.

## Applications of BK7 glass.

BK7 glass is widely used in various optical applications, including lenses, prisms, windows, and mirrors. Its excellent optical properties make it a popular choice for imaging systems, laser systems, and scientific instruments where high optical performance is required. BK7 glass is also commonly used in industrial applications, such as machine vision systems, metrology equipment, and optical sensors.

In conclusion, BK7 glass is a versatile material with excellent optical and mechanical properties that make it well-suited for a wide range of optical applications. Its high transmission, low dispersion, and good chemical resistance make it a popular choice for optical designers seeking high-quality optical components. By understanding the properties and characteristics of BK7 glass, users can confidently select the appropriate material for their specific optical requirements.

If you would like to learn more about BK7 glass or discuss your optical material needs, please feel free to contact us.

Contact us to discuss your requirements of Bi-Convex Lenses, custom right angle prisms, achromatic lenses. Our experienced sales team can help you identify the options that best suit your needs.