Plano Concave (PCV) Lenses have one flat and one inward curved surface. PCV lenses have a negative focal length and are used for image reduction or to spread light.
- Have negative focal lengths
- Diverge collimated incident light
- Forms only virtual images which are seen through the Lens
- Reduce spherical aberration, coma and distortion at negative-infinite or near-infinite conjugate ratios
- With the concave surface facing the longest conjugate distance
Bi-Concave Lenses are symmetrical with equal radii on both sides. The biconcave 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 utilizing biconcave lenses are laser beam expanders, optical character readers, viewers and projection systems.