Reasonable Concave Lens BK7 20mm Diameter -49.7mm Focal Length 400 - 700nm

S-SLB-20B-50NM

This lower cost product offering of Concave lenses has only minimal reduction in quality and is perfect for most applications. It can be used in an optical systems such as observation or lighting applications when the higher surface quality Concave Lens (SLB-N) is not required.
◦It has the same specification of Concave Lens (SLB-N) except the surface quality and is ideal for experiments and applications where high-precision is not required.
◦There are two types of lens offer, a Plano concave lens with low spherical aberration and a biconcave lens that is used to shorten the focal length.
◦In addition to uncoated products, there are three types of anti-reflection coating for visible, near-infrared, and infrared.
More Information
Name Reasonable Concave Lens BK7 20mm Diameter -49.7mm Focal Length 400 - 700nm
Weight 0.0500kgs
Standard Coatings Available No
Guide -
Remark -
Attention
  • Plano concave lens and biconcave lens has a chromatic aberration, and the focal length will vary depending on the wavelength. Please check the “wavelength characteristic of the focal length data” on “Technical Data” of Plano concave lenses (SLB-N) or Biconcave lenses (SLB-B-N) for the focal lengths of each wavelength.
  • WEB Reference Catalog Code/W3060-1, WEB Reference Catalog Code/W3050-1
  • Transmissions losses due to reflection off the front and rear surfaces of the lens can be minimized by coating the surfaces. Consult our Sales Division for anti-reflection coatings suitable for your application.
  • The outer edge of the concave side is chamfered and the result is possibility that the lens may have a smaller edge thickness for this design.
Diameter φD 20mm
Focal length −49.7mm
Material BK7
Design Wavelength 546.1nm
Refractive index n<sub>e</sub> 1.519
Centration <3′
Coating Broadband Multilayer antireflection coating (400 - 700nm)
Transmmittance > Average 99%
Laser Damage Threshold 4J/cm2 (Laser pulse width ; 10ns , Repetition frequency ; 20Hz)
Clear aperture 85% of the diameter
Surface Quality (Scratch-Dig) 60-40
Wavelength range of Antireflection Coating 400 - 700nm
Diameter φD φ20mm
Focal length f −49.7mm
Edge thickness te 3.9mm
Center thickness tc 2mm
Back focal length fb −50.3mm
Radius of curvature r 51.90mm
In stock
SKU
S-SLB-20B-50NM
$44.00

Delivery in : 6-12 weeks

This lower cost product offering of Concave lenses has only minimal reduction in quality and is perfect for most applications. It can be used in an optical systems such as observation or lighting applications when the higher surface quality Concave Lens (SLB-N) is not required.

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