Custom biconcave lenses

Biconcave Lenses for Diverging and Beam Expansion Optics

Kingsview Optical makes custom biconcave lenses to your drawing for OEMs, instrument makers and research labs. We polish them on our Optotech CNC lines in Rye, from 0.8mm to 100mm, then coat and measure them on the same site.

  • Made in Rye, East Sussex
  • CNC polished in Rye
  • Coated in-house
  • ISO 9001:2015
Send Your Lens Drawing See the Specification
Optotech CNC lens lines at Kingsview Optical in Rye
Our Optotech CNC lens lines, Harbour Road, Rye.
Lenses made here, start to finish. CNC polished, centred, coated and measured at our site in Rye.
See how we make them →
The basics

What a Biconcave Lens Does

In short: a biconcave lens has two concave surfaces, giving a negative focal length. It makes light diverge. An equiconcave lens, with equal radii, performs best when the input light is converging.

Biconcave lenses are used to expand beams, to reduce the convergence of light, to increase the effective focal length of a system, and as negative elements that balance the aberrations of positive lenses.

For diverging a collimated beam, a plano concave lens usually gives lower spherical aberration. A biconcave lens suits cases where the light entering it is already converging, or where the design calls for a symmetrical negative element.

Concave lenses are thinnest at the centre, so centre thickness is the key manufacturing limit. We'll advise on the minimum for your diameter.

Biconcave lens: two concave surfaces.
Ray trace of a biconcave lens diverging light
Ray trace of a biconcave lens, from our optical design software.
Applications

Where Our Biconcave Lenses Are Used

Beam expandersNegative elements in Galilean beam expanders.
Diverging opticsSpreading converging or collimated light.
Focal length extensionIncreasing the effective focal length of a system.
Wide-angle opticsNegative elements for wide fields of view.
Aberration balancingNegative elements in multi-element assemblies.
Scientific instrumentsResearch and laboratory optics.
Specification

Biconcave Lens Specification

These are our standard tolerances. If your design needs tighter, tell us which parameter. We'll tell you honestly whether we can hold it, and what it adds to cost.

Diameter range0.8mm to 100mm
Diameter tolerance+0 / −0.05mm
Centre thickness tolerance±0.05mm
Radius tolerance0.5% of radius or better
Irregularityλ/4
Centration (wedge)±2 arcmin
Surface quality (scratch-dig)60/40
MaterialsSchott, Ohara and CDGM optical glass; fused silica
CoatingsBroadband AR (standard 425 to 650nm, wider on request), V-coat, single-layer MgF2, custom designs
Edge finishingBlackened edges, steps, bevels, flats, controlled apertures

Not sure what to specify? For concave lenses, agree the minimum centre thickness early. It is the most common reason a design needs adjusting.

Options

Made to Fit Your System

CoatingsBroadband AR, V-coats and MgF2, applied in our own chambers
Edge featuresSteps, bevels, flats and blackened edges, CNC edged to suit your cell
Cells and housingsLens cells and barrels from our own machine shop AssemblyLenses fitted into cells and complete assemblies
Questions

Biconcave Lens Questions

Should I use a biconcave or a plano concave lens?
For diverging a collimated beam, a plano concave lens usually gives lower spherical aberration. A biconcave lens suits converging input light, or designs that need a symmetrical negative element.
What does a negative focal length mean?
The lens makes light diverge. Collimated light leaving it appears to come from a virtual focus on the input side, one focal length away.
Is there a minimum centre thickness?
Yes. A centre that's too thin for the diameter is hard to polish and can flex in use. Send your design and we'll confirm the minimum.
Can you make biconcave lenses in fused silica?
Yes. Alongside Schott, Ohara and CDGM optical glasses, we work in fused silica, which suits UV and high-power laser use.
What do you need to quote?
Diameter, the two radii or the focal length, centre thickness, glass, coating and quantity, or a drawing to ISO 10110 with the same information.

Other Lenses We Manufacture

Plano-convex Plano-concave Biconvex Biconcave Meniscus Achromatic doublets Achromatic triplets

Or see our full precision optical lens manufacturing capability, and our optical design service if you need a lens designed.

Getting a Quote for Biconcave Lenses

Send us your drawing or lens design data. An engineer from the team that would make your lenses, not a sales team, will review it. They'll tell you plainly what's achievable and what will drive cost.

What to send

  • Diameter, radii or focal length, or a drawing (PDF or ISO 10110)
  • Centre thickness
  • Glass type and wavelength
  • Coating requirement
  • Quantities: prototypes and expected production volumes

What happens next

  1. An engineer reviews itWithin one working day, flagging anything that will drive cost or lead time.
  2. We quote the lensFor the prototype, and for production at your volumes.
  3. We make, measure and deliverAll in Rye, with inspection data if you need it.
Start Your RFQ

Need a Custom Biconcave Lens?

Send your drawing or lens design data. We'll tell you honestly how we'd make it, what it will cost and how long it will take.

Send Your Lens Drawing Call 01797 226202
Made in Rye, East Sussex. NDA-friendly. Defence and security work welcome. ISO 9001:2015.