Optical Lenses

Spheric Lens

Spheric Lens

FOCtek provides five kinds of spheric lens forms, or shapes, that determine the imaging Characteristics
of the lenses, they are plano-convex, plano-concave ,Double-convex, Double-concave and Meniscus.

  • Plano-convex lens has a positive focal length, which makes it ideal for collecting and focusing light for many imaging applications.
  • Plano-concave lens has a negative focal length and is used for image reductinon or to spread light.
  • Double-convex lens has a positive focal length and is useful for 1:1 imaging and in multielement systems. also known as biconvex or equiconvex.
  • Double-concave lens has a negative focal length and is useful for 1:1 imaging and in multielement systems. also known as biconcave or equiconcave.
  • Meniscus lense has a positive or negative focal length, it forms a real or virtual image of objects.
 Plano Convex Lens  Plano Concave Lens  Double Convex  Lens
 Double Concave  Lens  Positive Meniscus Lens  Negative Meniscus Lens

Specifications of Spheric Lens

Attribute Specification
Material N-BK7, H-K9, Fused Silica, N-SF10, Silicon, CaF2, Sapphire etc.
Typical Diameter (Фmm) 10.0, 12.7, 15.0, 20.0, 25.4, 30.0, 50.8, etc.
Diameter Tolerance (mm) +0.0/-0.2 (General), +0.0/-0.02 (High Precision)
Paraxial Focal Length Tolerance (mm) ±2%
Centration <3 arc min
Clear Aperture >80% (Small Size), >95% (Large Size)
Surface Figure (per 25mm@632.8nm) <1.5λ, (General), <λ/4 (High Precision)
IRR ( @632.8nm) <λ/4 (General), <λ/10 (High Precision)
Surface Quality 60/40 (General), 10/5 (High Precision)
Bevel (face width x 450) <0.25mm
Coating uncoated, AR, HR, PR Coating, etc.

Note for Spheric Lens:
(1). Other optical glass materials from Schott or Chinese CDGM are also available upon request.
(2). Custom-made Spheric Lenses at any size from diameter 2.0mm to 300mm are available upon request.
(3). Typical paraxial focal length tolerance is ±2%, better tolerance is available upon request
(4). Typical centration is 3 arc minutes, better precision is available upon request.
(5). Besides uncoated,  Lenses with  Anti-Reflective(AR), High-Reflective(HR), Partial-Reflective(PR) coating are available upon request, Please refer to Part 4 OPTICAL COATING for more information about coating.


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