H-K9L / N-BK7 window
H-K9L / N-BK7 window
Definition: H-K9L, often referred to as N-BK7, is a high-quality borosilicate crown glass known for its excellent optical properties. It is widely used in the fabrication of precision optical components, particularly in applications requiring high transparency in the visible and near-infrared regions of the spectrum (350 nm – 2.0 µm). The refractive index (nd) of H-K9L is 1.5168, and its Abbe number (vd) is 64.20, making it a versatile material for various optical applications. This glass is RoHS-compliant, meaning it meets the environmental standards for hazardous substances.
H-K9L is recognized for its durability, with a hardness that allows it to withstand significant physical and chemical stresses. It is resistant to scratches and chemicals, which enhances its longevity in demanding environments. Additionally, H-K9L has a low bubble and inclusion content, which is crucial for maintaining the precision of optical lenses.
Comparison with Other Window Lenses: H-K9L (N-BK7) is often compared to other optical materials, such as UV fused silica, due to its widespread use and excellent transmission properties. However, unlike UV fused silica, H-K9L is not as effective in the ultraviolet (UV) spectrum, making it less suitable for applications requiring high UV transparency. Nonetheless, its cost-effectiveness and superior optical clarity in the visible and near-infrared regions make it a preferred choice for many applications.
Compared to other materials like SF11 or LaSFN9, which are used for high-index applications, H-K9L offers a lower refractive index, making it ideal for applications where minimal chromatic aberration and high light transmission are critical.
Applications: H-K9L (N-BK7) is one of the most commonly used optical glasses in the industry, particularly in the manufacturing of high-precision windows, lenses, and prisms. Its applications span various fields, including:
- Imaging Systems: Used in cameras, microscopes, and telescopes due to its excellent transmission properties in the visible spectrum.
- Laser Systems: Suitable for laser optics, where high precision and low absorption in the near-infrared region are required.
- Scientific Instruments: Commonly used in spectrometers and other analytical instruments where optical clarity and durability are essential.
- Medical Devices: Employed in optical components for medical imaging equipment.
- Industrial Applications: Used in metrology equipment and other devices that require precision optical components.
H-K9L windows can be customized with broadband anti-reflective (AR) coatings to enhance performance across specific wavelength ranges, such as 350 – 700 nm (VIS wavelength), 650 – 1050 nm, or 1050 – 1700 nm. This customization allows the windows to be tailored to specific application needs, further broadening their utility in various industries.