Dongguan Felix Glass Co., Ltd. E-mail: james@felixglass.com - Tel: +86 185 6503 2888
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K9 Optical Glass | Chinese Crown Optical Glass Substrate - Felix Glass

Oct 21,2026

K9 Optical Glass | Chinese Crown Optical Glass Substrate - Felix Glass

K9 Optical Glass

K9 optical glass is the widely used domestic crown optical glass, optically equivalent to N-BK7. It delivers stable optical performance, excellent homogeneity and low striae, which is a cost-effective substrate choice for visible and near-infrared optical designs.

Key Optical & Physical Properties

Parameter Specification
Transmission Range 350 nm – 2.2 μm
Refractive Index (@632.8nm) 1.5168
Abbe Number 64.17
Knoop Hardness 610 Knoop
Density 2.51 g/cm³
Coefficient of Thermal Expansion 7.1 ×10⁻⁶ /K

Common Optical Components We Fabricate

  • K9 spherical lenses: plano-convex, plano-concave, biconvex and biconcave lenses
  • K9 optical flat windows, cover plates and protective substrates
  • Right-angle prisms, equilateral prisms, beam splitter prisms
  • Custom K9 blanks, optical wedges and gauge flats

Available Coating Options

We provide standard coatings optimized for K9 visible and near-infrared optical parts:

  • Broadband AR coating for visible band 400–700 nm
  • Single wavelength AR coating for 532nm, 633nm, 1064nm
  • VIS-NIR anti-reflection coating
  • Aluminum / chromium reflective coating for prisms and mirrors

Typical Application Fields

  • Machine vision and industrial inspection optics
  • Optical laboratory and teaching experimental equipment
  • Low-power visible laser alignment and beam shaping
  • Optical measurement instruments, autocollimators
  • Consumer imaging and general optical assemblies

Machining Capacity & Quality Control

Felix Glass processes premium grade K9 optical glass with strict internal inspection. Surface scratch-dig grade up to 20/10, surface flatness can reach λ/10 @632.8 nm. We support round, square, rectangular and angled K9 optics, with tight angular and dimensional tolerance for prototype sampling and bulk production orders.

Datasheet & Custom Inquiry

Download our K9 glass datasheet for full dispersion curve and optical parameters. Send your technical drawing, target wavelength and coating requirements to get your custom quotation.

Request Datasheet & Custom Quote

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James Fu, Sales Director of FELIX OPTICAL GLASS, and a poster displaying contact information for an optical glass deep-processing factory.James Fu, Sales Director of FELIX OPTICAL GLASS, and a poster displaying contact information for an optical glass deep-processing factory. 2
Learn more from our FAQ
What is the minimum order quantity for custom precision optical glass components?

FELIX OPTICAL GLASS offers highly flexible MOQs to support customer projects, including prototype testing, small-batch trial orders, and high-volume production. All products can be fully customized to your drawings, tolerances, and application standards. Please send us your specifications, and we will reply within 1-5 hours and provide an accurate quotation after careful evaluation within 1-2 days.

Can I get free glass samples for testing before bulk order?

Yes, our FELIX GLASS factory supports sample testing for a wide range of precision optical glass components and assemblies. The lead time for sample production is 3 to 7 working days. Please contact us today to arrange samples and obtain a customized solution that meets your needs.

What is the production lead time for custom optical glass components?

A: The production cycle for standard samples is 3-10 working days, while mass production requires 15-35 working days, depending on the complexity of the product and the order quantity. We provide reliable precision optical glass components and fast delivery services for orders from industries such as defense, industrial equipment, medical devices, shipbuilding, robotics, automotive, and aerospace. Please submit your project details so we can provide you with an accurate delivery schedule.

Are your optical glass products ISO, CE and RoHS certified?

All precision optical glass components from FELIX OPTICAL GLASS comply with ISO quality system standards as well as CE and RoHS requirements. We provide comprehensive test reports, spectral graphs, material certificates, and inspection documents for customer review. Please feel free to request complete certification details and a formal quotation at any time.

Do you offer one-stop custom optical glass processing services?

Yes. We offer a full range of precision optical glass component processing services, including CNC machining, precision grinding, optical polishing, chemical/physical tempering, vacuum coating (AR anti-reflective coating, AF anti-fingerprint coating, AG anti-glare coating, IR infrared coating), and screen printing. From raw materials to finished products, every step is completed in our own factory. Please tell us your needs, and we will provide you with the most cost-effective solution.

CONTACT US NOW FOR A QUOTE
We will respond promptly within 1 to 5 hours and provide an optimal, formal quotation within 1 to 2 days. Partnering with us is the smartest choice—start a mutually beneficial partnership today!
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With 19 years of experience as a precision optical glass expert, we provide comprehensive and satisfactory customized solutions.

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