
Our BK7 double-concave lens has two inwardly curved surfaces and a negative focal length. It is commonly designed for image shrinking and light dispersion. There are thousands of ready-made radiuses of curvature model in our company. Also, we can supply the custom-made products.
 Technical Specifications
Technical Specifications
    Material: BK7
    Diameter Tolerance: +0/-0.1mm
    Thickness Tolerance: ±0.2mm
    Flatness: λ/4 @632.8nm
    Clear Aperture: 90%
    Focal Length Tolerance: +/-1%
    Surface Quality: 40-20
    Bevel: <0.25mm x 45 º
    Design Wavelength: 587.6nm
    Centration: 3 arc min
    
Note: The price per unit of common single wavelength anti-reflection coating is shown below. However, the actual price will fluctuate frequently due to the influence of size, time, quantity, and exchange rate. If you want to know of the current price, you can contact us immediately. Moreover, please skim through the page of coating film on our website for more information.
| Catalog No. | Diameter (mm) | Effective FL(mm) | Back FL(mm) | Radius R1=-R2 (mm) | Center Thickness (mm) | Edge Thickness (mm) | Price-Uncoated | AR@1064nm double Sides | |||
| 5--10 | 50-100 | 10.0 | 50.0 | 100.0 | |||||||
| BJP-L1B-06-012 | 6 | -12 | -12.87 | -12.85 | 2.72 | 3.43 | $19.4 | $12.9 | $51.6 | $21.0 | $17.7 | 
| BJP-L1B-06-018 | 6 | -18 | -18.76 | -19.00 | 2.37 | 2.85 | $19.4 | $12.9 | $51.6 | $21.0 | $17.7 | 
| BJP-L1B-06-024 | 6 | -24 | -24.72 | -25.18 | 2.22 | 2.58 | $19.4 | $12.9 | $51.6 | $21.0 | $17.7 | 
| BJP-L1B-12-018 | 12 | -18 | -18.76 | -19.00 | 2.37 | 4.31 | $21.0 | $13.7 | $53.2 | $21.8 | $18.5 | 
| BJP-L1B-12-024 | 12 | -24 | -24.72 | -25.18 | 2.22 | 3.67 | $21.0 | $13.7 | $53.2 | $21.8 | $18.5 | 
| BJP-L1B-12-030 | 12 | -30 | -30.56 | -31.30 | 1.72 | 2.88 | $21.0 | $13.7 | $53.2 | $21.8 | $18.5 | 
| BJP-L1B-20-030 | 20 | -30 | -30.56 | -31.30 | 1.72 | 5.00 | $24.2 | $15.3 | $56.5 | $23.4 | $20.2 | 
| BJP-L1B-20-040 | 20 | -40 | -40.49 | -41.60 | 1.50 | 3.94 | $22.6 | $14.5 | $54.8 | $22.6 | $19.4 | 
| BJP-L1B-20-060 | 20 | -60 | -60.69 | -62.37 | 2.10 | 3.71 | $22.6 | $14.5 | $54.8 | $22.6 | $19.4 | 
| BJP-L1B-25-040 | 25 | -40 | -40.49 | -41.60 | 1.50 | 5.35 | $27.4 | $17.7 | $59.7 | $25.8 | $22.6 | 
| BJP-L1B-25-060 | 25 | -60 | -60.69 | -62.37 | 2.10 | 4.63 | $25.8 | $16.9 | $58.1 | $25.0 | $21.8 | 
| BJP-L1B-25-080 | 25 | -80 | -80.70 | -83.05 | 2.14 | 4.03 | $25.8 | $16.9 | $58.1 | $25.0 | $21.8 | 
| BJP-L1B-40-050 | 40 | -50 | -50.65 | -52.02 | 2.00 | 10.00 | $30.6 | $21.0 | $62.9 | $29.0 | $25.8 | 
| BJP-L1B-40-070 | 40 | -70 | -70.83 | -72.78 | 2.53 | 8.13 | $29.0 | $19.4 | $61.3 | $27.4 | $24.2 | 
| BJP-L1B-50-100 | 50 | -100 | -100.82 | -103.79 | 2.51 | 8.62 | $33.9 | $22.6 | $66.1 | $30.6 | $30.6 | 
| BJP-L1B-50-200 | 50 | -200 | -200.83 | -207.15 | 2.52 | 5.55 | $32.3 | $21.8 | $64.5 | $29.8 | $29.8 | 
