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Our technical experts are here to assist you. For optical solutions to suit your needs

Why use a ball & half ball lenses?

Ball lenses are, as the name suggests, completely spherical lenses most commonly used to improve the coupling of light in and out of fibres, detectors and emitters. Dependent on the geometry of the light source, ball lenses either focus or collimate light (a collimated source will focus the light). Both ball and half ball lenses must be produced with materials which have a refractive index less than 2. This is because any refractive index greater than 2 will have a focal length which is less than the radius of the lens. 


Ball lenses help keep us connected

Due to their effectiveness, relative low cost and often small size, ball lenses have maintained their position within the telecommunications industry despite technological advances. New high-bandwidth communications including fibre-to-fibre, diode-to-fibre and diode-to-diode assemblies demand efficient coupling and collimating devices used in laser systems and data transfer.
Ball lenses are commonly produced from sapphire as the material has excellent internal transmission as well as an optimum refractive index (1.76). The high refractive index consequently offers a short focal length, enabling ball lenses to be implemented in systems with very limited space. 


Half ball lenses help keep our roads safe

In modern LED traffic light systems half ball lenses are not used for their ability to focus light. On the contrary, they are used in complete displays to facilitate uniform dispersion of steady, visible light to road users and pedestrians.
As traffic light systems do not require precision grade half ball lenses due to their application, everyday materials such as BK7 may be used. BK7 transmits over 90% of light in the visible spectrum, making this material a cost-effective option compared to more specialist alternatives. 

Custom ball and half ball lenses from Knight Optical

Knight Optical offers a range of competitively priced ball and half ball lens custom solutions to suit your requirements. Custom sizes of ball lenses range from 0.13mm-50mm with a wealth of different material options, from ruby to UV grade fused silica which is used down to 175nm. We are able to supply high precision grade 3 ball lenses, mid-range grade 25 ball lenses and commercial grade 100 ball lenses offering all grades to suit any application. We also hold a vast stock of ball and half ball lenses that are not visible on our ecommerce site, so please enquire.
Our custom sapphire and ruby ball lenses have a high refractive index which gives quite low spherical aberration. Custom sapphire ball lenses have excellent transmission from 200nm up to 5000nm, so can also be can be used for UV, visible and IR applications. Custom ruby ball lenses have good transmittance above 650nm, so can be used in the IR region. Other common materials used for custom ball lenses are S-Lah79 that has a high refractive index of 2.003 and good transmission from 300nm to NIR at 2000nm, BaF-8, Lasfn9, Lasfn35, Lah78 cubic zirconia and ceramic.
Our range of custom ball lenses can be antireflective coated at NIR wavelengths such as 1310nm and telecoms 1050-1650nm. 

Our typical custom ball lenses capabilities:

Diameter: 0.15mm to 30mm+
Diameter tolerance (sphericity): < 0.075μm
Basic diameter tolerance: +/-0.5μm
Surface roughness: (Ra) < 0.007μm
Grades: 3 to 200. (see our information sheet here)
Material: UV Fused Silica, Ruby, Cubic Zirconia, Sapphire, Ceramic, (Al2O2, ZrO2, SI3N4), Quartz, Schott/ Hoya Glass or equivalents. (Lasfn35, Lasfn9, S-LAH79, S-LAL8, N-LAK10, S-LAH78) 

Super-Hemispherical/ Hyper-Hemispheric ball lenses are also available in a range of materials and custom designs.

More information on the achievable specifications for your individual application can be found by contacting our technical sales team. 

Stock ball and half ball lenses from Knight Optical

Knight Optical stock a range of ball and half ball lenses with diameters 0.5mm-10mm and focal lengths 0.345mm-8.69mm. Materials stocked include BK7 as well as UV fused silica and sapphire, for those applications outside of the visible spectrum.

At Knight Optical we pride ourselves on the quality of our products and service therefore every component is 100% QA inspected. Optics are tested by our highly skilled technicians in our state-of-the-art metrology lab to ensure all parts meet our high quality standards.

To learn more about how our Quality Germanium solutions can improve your application and your supply chain experience, contact our multilingual technical sales team

ISO Standard

Knight Optical is very proud to be certified for ISO14001 for Environmental Management and ISO9001 for Quality Management Systems. These certifications demonstrate our commitment to maintaining competence and reliability in the supply, metrology testing and inspection of our products.

ISO 14001: Environmental Management we strongly believe that all businesses should be mindful of their environmental impact and seek to manage this effectively in their day to day activities. Green energy, recycling, carbon footprints and other environmental issues are very real concerns and we feel it is important to demonstrate to our customers our commitment to minimising our environmental impact.

Knight Optical has adopted and been certified for ISO 14001: Environmental Management System to comply with our environmental obligations. Our EMS framework allows us to have a systematic approach to the way we handle the challenges brought on by our commitment to environmental standards.


ISO 9001: Quality Management Systems quality should be consistent and customers should expect the same high quality service and products every time they order from us. In being certified for ISO9001, we are able to constantly monitor the way we work and ensure a consistently high level of service. We have well defined and documented procedures to ensure consistency and allow for corrective measures to be quickly applied should faults be found.

Our ISO9001 procedures give our management a clear and concise picture of how the company is performing. This mechanism of reviewing goals and performance aids us in our efforts to push forwards and improve as our company grows.


At Knight Optical we pride ourselves on the quality of our products and service. Every component is individually tested by our highly skilled technicians in our state-of-the-art metrology lab to ensure all parts meet our high quality standards. Our metrology laboratory is well equipped with the latest optical measurement technology including our ZYGO Verifire interferometer for form and Trioptics OptiSpheric for focal length and radius testing. All our coatings are thoroughly tested on our Cary 5000 spectrophotometer with new UMA reflectance attachment.

For more information on our metrology and testing capabilities

Inside Knight Optical’s catalogue you’ll find details of the industries we serve as well as the many other services we can offer. It also showcases hundreds of our most popular products, supported by useful technical information, to help you choose the right part for your application.

Our 2018/2019 Catalogue

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