Plano Concave Lenses for Beam Expansion and Diverging Optics
Kingsview Optical makes custom plano concave 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
What a Plano Concave Lens Does
In short: a plano concave lens has one flat surface and one concave surface, giving a negative focal length. It makes a collimated beam diverge, as if it came from a point in front of the lens.
Plano concave lenses are used to expand beams, to increase the focal length of a system, and as negative elements that balance the aberrations of positive lenses. For the lowest spherical aberration, face the curved surface towards the larger conjugate, usually the collimated beam.
In a Galilean beam expander, a plano concave lens is paired with a positive lens. There is no internal focus, which makes the design compact and well suited to high-power lasers.
Concave lenses are thinnest at the centre, so centre thickness is the key manufacturing limit. We'll advise on the minimum for your diameter so the lens stays stable during polishing and in use.
Where Our Plano Concave Lenses Are Used
Plano Concave 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 range | 0.8mm to 100mm |
|---|---|
| Diameter tolerance | +0 / −0.05mm |
| Centre thickness tolerance | ±0.05mm |
| Radius tolerance | 0.5% of radius or better |
| Irregularity | λ/4 |
| Centration (wedge) | ±2 arcmin |
| Surface quality (scratch-dig) | 60/40 |
| Flatness (plano surface) | λ/4 @ 633nm |
| Materials | Schott, Ohara and CDGM optical glass; fused silica |
| Coatings | Broadband AR (standard 425 to 650nm, wider on request), V-coat, single-layer MgF2, custom designs |
| Edge finishing | Blackened 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.
Made to Fit Your System
Plano Concave Lens Questions
Which way round should a plano concave lens face?
What does a negative focal length mean?
Why use a plano concave lens in a beam expander?
Is there a minimum centre thickness?
What do you need to quote?
Other Lenses We Manufacture
Or see our full precision optical lens manufacturing capability, and our optical design service if you need a lens designed.
Getting a Quote for Plano Concave 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 and focal length or radius, or a drawing (PDF or ISO 10110)
- Centre thickness
- Glass type and wavelength
- Coating requirement
- Quantities: prototypes and expected production volumes
What happens next
- An engineer reviews itWithin one working day, flagging anything that will drive cost or lead time.
- We quote the lensFor the prototype, and for production at your volumes.
- We make, measure and deliverAll in Rye, with inspection data if you need it.
Need a Custom Plano Concave 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.
Made in Rye, East Sussex. NDA-friendly. Defence and security work welcome. ISO 9001:2015.