Ball & Half Ball Lenses

Ball, and half ball lenses, are key components in a wealth of applications due to their small size (usually < 10mm), ease of positioning and alignment due to their complete rotational symmetry, and relatively low cost.

These completely spherical lenses are most commonly used to improve the coupling of light in and out of fibres, detectors and emitters. They are widely used in the telecommunications industry where new high-bandwidth communications, including fibre-to-fibre, diode-to-fibre and diode-to-diode assemblies, demand efficient coupling and collimating optics.

In modern LED traffic light systems, hemispherical (half ball) lenses are used to uniformly disperse light rather than collimate it. Half ball lenses can also be used in place of ball lenses where there are space constraints.

Knight Optical offers a range of competitively priced ball and half ball lens custom solutions to suit your requirements. We can offer diameters ranging from micro optics of 0.13mm in diameter up to larger 150mm diameters. All our ball and half ball lenses can be manufactured at different grades to ensure you are getting the specifications you need, these range from high precision grade 3 (with high sphericity and surface quality) to more commercial grade 100 ball lenses, you can find more information on the grades we offer here.

A wide range of material options are available to cover UV to IR applications:

• BK7 (or equivalent) and UV fused silica (UVFS) are standard materials used for UV and visible applications, with UVFS transmitting down to 175nm, and both transmitting well between 400-700nm.
• Materials with high refractive indices are often used as they produce a shorter back focal length and therefore higher efficiency fibre coupling, for example, S-LAH79 (2.003), LASFN9 (1.8502), LASFN35 (2.022) and LAH78 (1.9013).
• Sapphire and ruby, both with the composition Al₂O₃, are ideal substrates for ball lenses. They offer high durability for harsher environments with high chemical stability. Sapphire has excellent transmission between 200nm to 5µm and therefore can be used in UV, VIS and NIR applications, whilst ruby transmits well from 650nm so can be used in IR applications. They also have a high refractive index so offer more efficient coupling.
• For IR applications, silicon can be used which transmits well in the MWIR region of 3-5µm, but can also transmit over 1.2-15µm.
• Other materials to consider are quartz, ceramic, cubic zirconia, spinel, S-LAL8, N-LAK10 and N-SF8.

Knight Optical has a large range of stock ball and half ball lenses, both uncoated and AR coated, which can be found here. These range from 0.5 to 10mm in diameter, with a surface quality of < 40/20 scratch/dig.

Sizes of all the materials we can offer are as follows;

Contact our multilingual technical sales team and discover how Knight Optical’s high quality, custom and stock ball and half ball lenses, along with our impeccable level of service, can improve your instrumentation and supply chain experience.