Overview:
A special form of a thick biconvex optical lens is a ball lens, usually having the geometrical form of a ball (sphere). They are manufactured from a single material, usually an optical glass with good transparency in the wavelength region of interest. A frequently used material is fused silica.

Ball lenses and can focus or collimate light, depending upon the geometry of the input source. They are great optical components for improving signal coupling between fibers, emitters, and detectors. They are also used in endoscopy, bar code scanning, ball pre-forms for aspheric lenses, and sensor applications.

Ball lenses are usually made with relatively small diameters of a few millimeters or sometimes even less than 1 mm (microlenses). Particularly for such small dimensions, they are easier to fabricate than lenses with traditional designs.

Another variant are half-ball lenses, which are obtained simply by cutting ball lenses in half.
Half-ball lenses are also common and can be interchanged with full ball lenses if the physical constraints of an application require a more compact design.

Star Optic provides ball lenses and half ball lenses made from various substrate materials including sapphire, ruby, BK7, UV fused silica, high index glass, and germanium, ZnSe, ZnS with AR coating.

Available diameters are between 0.3 mm to 100 mm, with diameter tolerance (sphericity) <0.3 µm and surface roughness (Ra) <0.007 µm. Custom ball and half ball module options are also available on request.

There are five key parameters needed to understand and use ball lenses: Diameter of Input Source (d)(d), Diameter of Ball Lens (D), Effective Focal Length of Ball Lens (EFL), Back Focal Length of Ball Lens (BFL)and Index of Refraction of Ball Lens (n).


General Specifications of BK7 Ball Lens:

Material	N-BK7
Diameter Tolerance	+0/-0.005mm
Surface Quality	60/40 scratch-Dig
Sphericity	<0.003mm
Clear Aperture	>90%
Coating	None, Available

Standard Products of BK7 Ball Lens: