Full performance of optical H-K9L / BK7 glass
H-K9L is the Chinese made equivalent material of N-BK7. N-BK7 is the RosH compliance material of BK7. N-BK7 is a borosilicate crown optical glass.
VY Optoelectroics Co.,Ltd. produce optical elements by different optical material, H-K9L glass is the main material for our factory to manufacture lenses, we choose the best grade of H-K9L glass from the biggest and famous glass manufacturer- CDGM.
H-K9L is a high quality optical glass used in lenses and other optical components where the additional benefits of Fused Silica are not required. It is a relatively hard material with extremely high homogeneity, low bubble and inclusion content. H-K9L has a low refractive index (≈1.52), low dispersion, and provides excellent transmittance through-out the visible and near infrared spectra, down to 350 nm in the ultraviolet.
Its good physical and chemical properties make it widely used in visible and near IR range. Most of windows, lenses and prisms, which used in laser, optical system, optical communication, are made from N-BK7/H-K9L glass.
Special properties of BK7/H-K9L
• High optical quality
• Made of the purest raw materials
• Colorless apperance and very clear looking
• Nearly free of bubbles
• Nearly free to inclusions
Typical applications of H-K9L glass
• Protective windows for laser applications
• General optical applications
• Optical items like lenses and prisms
• Mirror substrates
• Subtrates for optical coatings
H-K9L(N-BK7)composition
SiO2 | B2O3 | BaO | Na2O | K2O | As2O3 |
69.13% | 10.75% | 3.07% | 10.40% | 6.29% | 0.36% |
Properties of H-K9L glass
Thermal Properties | |
Thermal Coefficient of Expansion(0/300°C) | 70 X 10 -7/°C |
Annealing Point | 550°C / 1022 °F |
Softening Point | 719°C / 1326 °F |
Strain Point | 624°C / 1155 °F |
Mechanical Properties | |
Density | 2.51 g/cm3 |
Knoop Hardness | 610 |
Young's Modulus | 8.20 X 109 dynes/mm2 |
Poisson's Ratio | 206 |
Optical Properties | |
Refractive Index | 1.509 |
Chemical Properties | |
Hydrolytic Resistance | class 2 |
Acid Resistance | class 1 |
Alkali Resistance | class 1 |
Optical transmission in the VIS of K9 glass and BK7 Glass
Below is a video to show how VY Optoelectronics Co., Ltd. produce optical K9 glass lenses, please contact us freely if you are interested in our product. Beside H-K9 glass lens, our company also manufacture and design other optical material lens, such as B270 glass, Sapphire glass, SF11 glass, ZnSe, Germanium and other infrared glass.
VY Optoelectronics Co., Ltd. manufacture large quantity of optical lenses with material of K9 glasses, due to its high performace price ratio. Customers usually choose K9 as material, we produce dome lens, window, filter, prism, cylindrical lens, spherical lens, aspheric lens, powell lens, collimating lens etc. in such material, the quality is perfect for application.
If you are interested in designing or processing any optical elements or laser products, please contact us for more details, we are a factory in China who is professional at fabricating lenses. It will be our great pleasure if we can supply any solution for your optical system.