N-BK7 bi-concave lenses have equal radius of curvature on both surfaces. Bk7 bi-concave lenses are often used to expand light beams or to increase focal lengths in optical systems, and are normally used in combination with other lenses. Among the many devices using bi-concave lenses are laser beam expanders, optical character readers, viewers and projection systems. The lenses have features as follows:
● Low cost, high performance for N-BK7 optical glass.
● Bi-concave lenses for beam expansion use.
● Great optical transmission.
Custom made specifications:
| Substrate | N-BK7 or H-K9L |
| Diameter tolerance | +/-0.05mm or better |
| Thickness tolerance | +/-0.05mm |
| S/D | 40-20 or better |
| Surface figure | Lambda/4 |
| Centering | 1 arc min |
| Bevel | Protective bevel |
| Coating | AR coated @visible wavelength or NIR, R<0.5% |
| RoHS | Certificated |
We have the lenses below in stock:
|
Dia(mm) |
EFL(mm) |
Centering |
Scratch and Dig |
|
10 |
10.12 |
3' |
3*0.16 |
|
12.7 |
19.98 |
3' |
3*0.16 |
|
12.7 |
50.2 |
3' |
3*0.16 |
|
12.7 |
100.4 |
3' |
3*0.16 |
|
22.4 |
19.84 |
3' |
3*0.25 |
|
22.4 |
30.02 |
3' |
3*0.25 |
|
22.4 |
40.11 |
3' |
3*0.25 |
|
22.4 |
50.3 |
3' |
3*0.25 |
|
22.4 |
100.4 |
3' |
3*0.25 |
|
22.4 |
150.34 |
3' |
3*0.25 |
|
25.4 |
50.2 |
3' |
3*0.25 |
|
40 |
504.08 |
3' |
3*0.16 |
