The double concave lenses with the negative focal length, these lenses are used in Beam Expanders, optics image, laser system and so on.
Our bi concave lens — also known as a double concave lens — is a precision optical component with two inward‑curved spherical surfaces designed to diverge collimated light and produce a virtual image. Ideal for beam expansion, image reduction, and sophisticated optical system integration, our double concave lenses deliver consistent optical performance for industrial, scientific, and imaging applications.
These lenses feature negative focal lengths and are widely used to control beam profiles, extend effective focal lengths in multi‑element systems, or reduce aberrations in optical setups. With options for high precision tolerances, advanced anti‑reflective coatings, and multiple optical glass materials, our bi concave lenses are engineered for reliability and superior optical quality.
As a leading Spherical Lenses Manufacturer, we provide precision-crafted bi-concave lenses that guarantee superior optical performance for all your projects.
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Parameter
| Structure | Bi Concave Lens |
| Material | Optical glass, UVFS, Germanium, Silicon, CaF2, MgF2, ZnSe ZnS, Sapphire |
| Diameters Available | 0.5mm to 600mm |
| Diameter Tolerance | +0.00/-0.01mm or customer design |
| Surface Quality | 10-5 |
| Surface Irregularity | λ/10 PV @632.8nm or customer design |
| Thickness tolerance | +0/-0.01mm |
| Clear Aperture | >90% of Diameter |
| Chamfer | 0.05-0.5mmx45degree |
| Centeration | <10 arcsec |
| Coating | Single Mag2, Multiple Layers AR Coating A:350-650nm B:650-1050nm C:1050-1585nm D: Customer Design |
Bk7 Standard Double Concave Lens
| No. | EFL(mm) | Dia.(mm) | R1=R2(mm) | Material | Tc(mm) | Te(mm) |
| SD4A12 | -20 | 12.70 | 21.08 | Bk7 | 2.00 | 3.96 |
| SD4A13 | -30 | 12.70 | 31.48 | Bk7 | 2.00 | 3.29 |
| SD4A14 | -40 | 12.70 | 41.48 | Bk7 | 2.00 | 2.97 |
| SD4A15 | -50 | 12.70 | 52.24 | Bk7 | 2.00 | 2.78 |
| SD4A25 | -50 | 25.40 | 52.17 | Bk7 | 2.00 | 5.10 |
| SD4A27 | -75 | 25.40 | 78.09 | Bk7 | 2.00 | 4.10 |
| SD4A210 | -100 | 25.40 | 104.00 | Bk7 | 2.00 | 3.60 |
| SD4A215 | -150 | 25.40 | 156.00 | Bk7 | 2.00 | 3.00 |
| SD4A220 | -200 | 25.40 | 207.66 | Bk7 | 2.00 | 2.80 |
| SD4A225 | -250 | 25.40 | 259.49 | Bk7 | 2.00 | 2.60 |
The optical path diagram of the imaging law of concave lenses
Features & Benefits
✔ Negative Focal Length & Beam Divergence – Double concave lenses naturally diverge incoming parallel light, enabling beam shaping and manipulation in complex optical systems.
✔ Wide Material Selection – Choose from BK7, UV fused silica, germanium, silicon, CaF₂, MgF₂, ZnSe and other advanced optical materials.
✔ Custom Diameters & Tolerances – Standard diameters from 0.5mm up to 600mm (or custom per your design), with tight diameter and focal length tolerances available.
✔ High‑Precision Surface Quality – Options up to 10‑5 scratch‑dig, low irregularity, and high clear aperture ensure minimal wavefront distortion.
✔ Advanced Coating Options – Single or multi‑layer AR coatings across visible, NIR and customized spectral bands.
Our bi concave / double concave lenses are commonly used in:
Beam expanders and laser systems
Optical imaging and projection
Collimators and telescope systems
Scientific research and laboratory optics
Laser scanning and sensor applications
Why Choose Sunday Optics
· Experienced Manufacturer – Over a decade of expertise in designing and producing high-quality spherical lenses.
· Precision and Quality – Every lens is crafted to exact specifications, ensuring minimal aberration and high clarity.
· Custom Solutions – We offer customization in size, coating, and material to meet your unique requirements.
· Global Delivery – Reliable shipping to customers worldwide with professional support at every step.
· Competitive Pricing – High-quality lenses at reasonable prices, maximizing value for your investment.
Q1: What materials are your bi-concave lenses made of?
A1: We manufacture lenses from optical glass, BK7, and other high-quality materials suitable for various applications.
Q2: Can I customize the lens specifications?
A2: Yes, we provide custom diameters, focal lengths, and anti-reflective coatings to match your project needs.
Q3: What industries use your spherical lenses?
A3: Our lenses are used in optical instruments, laser systems, imaging devices, research labs, and educational applications.
Q4: How is the quality of your lenses ensured?
A4: Each lens undergoes strict inspection, including surface quality testing, focal length accuracy, and coating verification.
Q5: Do you ship internationally?
A5: Yes, we ship worldwide with secure packaging and reliable logistics partners.
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