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Lenses

Lenses have many applications ranging from simple light collection to precise imaging and image transfer. Lenses are classified as single lenses, cylindrical lenses and achromatic lenses according to the different applications.

LENSES
MATERIAL
ILLUSTRATION
PROPERTY & APPLICATION

Plano-convex

BK7 Fused Silica
Sapphire CaF2
plano convex lens
Positive focal length. Most suitable where one conjugate is more than five times over the other, e.g. in sensor application or for use with near collimated light. Also where both conjugates are on the same side of the lens. e.g. as in add-on lens to increase the numerical aperture.

Double-convex

BK7 Fused Silica
double convex lens
Most suitable where the conjugates are on opposite sides of the lenses and the ratio of the distances is less than 5:1, e.g, as simple image relay components.

Plano-concave

BK7Fused Silica
Sapphire CaF2
plano concave lens
Negative lens with the form most suitable where one conjugate is more than five times the other, e.g. producing divergent light from a collimated input beam.

Double-concave

BK7 Fused Silica
double concave lens
Negative lens with the form most suited to producing diverging light or virtual images, where the input light is converging.

Meniscus
Positive

BK7
meniscus positive lens
These lenses may be used to increase the numerical aperture of a positive lens assembly without undue increase in the aberrations.

Meniscus
Negative

BK7 Fused Silica
Sapphire CaF2
meniscus negative lens
The best lens from where one conjugates is relatively far from the lens, or where both conjugates are the same size as the lens.

Cylindrical

BK7 Fused Silica
cyclindrical lens
Used to provide focusing power in one section only. For illumination or detection of light from line sources. Also use for anamorphic compression of beams and images

Achromatic

Combinations of
two Optical grade
glasses
achromatic lens
These lenses have considerably reduced values of spherical aberration, and chromatic aberration. Best used to replace single components where performance must be improved.

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