A lens having at least one surface that is formed like a portion of a cylinder.
Stretching a point image into a line image.
Changing the height of an image without affecting its width.
Used to correct astigmatism in the eye and in rangefinder, to produce astigmatism. Primarily for use in illumination systems.
Manufacturing Tolerances
Attribute |
Commercial standard |
Precision Standard |
Material |
BK7, fine annealed |
BK7, fine annealed, Fused silica |
Focal Length |
546.1nm |
±2% |
Dimensional (Φ) |
±0.25mm |
±0.15mm |
Center Thickness (t) |
±0.25mm |
±0.15mm |
Cosmetics (scratch-dig) |
80-50,60-40 |
20-10, 10-5 |
Centering Error (Arc Min) |
5 |
3,2 |
Edges |
Fine ground and beveled |
Fine ground and beveled |
Clear Aperture |
90% |
90% |
Coating |
See attached coating chapter |
See attached coating chapter |
All dimensions are in mm unless otherwise specified.
Different material, sizes, tolerance and coating are available upon request.
