Understanding the Difference: BK7 vs. Domestic K9 Optical Glass
optical material
positive optics team
3/5/20261 min read
In the field of precision optics, material selection plays a key role in determining performance and cost. Two commonly compared materials are BK7 and China's domestic K9 optical glass.
BK7, developed by Schott in Germany, is a borosilicate crown glass widely recognized for its excellent optical clarity, homogeneity, and resistance to chemical damage. It is often the industry standard for high-precision lenses and prisms used in laser applications and scientific instruments.
Domestic K9, on the other hand, is the Chinese equivalent to BK7. While the two materials share nearly identical optical properties (such as refractive index and Abbe number), K9 is typically produced to meet local manufacturing standards and is more cost-effective.
In many commercial applications, K9 serves as a reliable substitute for BK7. However, for high-end scientific or aerospace projects where extreme precision and certification are required, original BK7 remains the preferred choice.
Understanding these differences helps us provide the right material for the right application—ensuring both quality and value for our customers.
Changchun Positive Optics support all kinds of optical material to meet your custom optics requirement. Welcome your any time inquiry! Our mail is info@pooptics.com