What is the difference between concave convex and cylindrical lense?
CYLINDRICAL LENS This is the full information about the cylidrical lenses, but my advice would be- not to read it -because it is not in your syllabus. Just the definition would be enough which is "Acylindrical lensis alenswhich focuses light into a line instead of a point, as a sphericallenswould. The curved face or faces of acylindrical lensare sections of acylinder, and focus the image passing through it into a line parallel to the intersection of the surface of thelensand a plane tangent to it." Cylinder lenses are a type of lens that have differing radii in the X and Y axes, causing the lens to have a cylindrical or semi-cylindrical shape, and image magnification in only a single axis.Cylinder lensesare commonly used as laser line generators, or to adjust image height size or correct for astigmatism in imaging systems.
Figure 1:Plano-Convex Circular Cylinder Lens 
Figure 2:Plano-Convex Rectangular Cylinder Lens 
Figure 3:Plano-Convex Oblong Cylinder Lens Creating a Laser Line Generator When using a cylinder lens as a laser line generator, it is important to calculate the required Effective Focal Length (EFL) for the application. To do so, first calculate the fan angle (θ) using the needed line length (x) at the given working distance (L) in centimeters:
(1) The fan angle can also be used to determine the line length at a given working distance:
(2) 
Figure 4:Visual Illustration of Equations 1 – 2 for Creating a Laser Line Generator The EFL can then be calculated using the input beam radius (d/2) and the following equation:
(3) 
Figure 5:Visual Illustration of Equation 3 for Calculating Effective Focal Length Creating Circular Beams Typically,laser diodesemit elliptical shaped beams that may be unsuitable for applications that require a collimated, circular laser source. Using twocylinder lensesis a common method to circularize an elliptical beam - the first lens magnifies the minor axis of the laser diode, and the second lens collimates the beam. The curved side of the lenses and the minor axis of the laser diode should be oriented so that the minor axis is being magnified.
For example, to modify an elliptical beam with a 4.0mm major axis and a 1.0mm minor axis to a circular beam with a 4.0mm diameter, the minor axis needs to be magnified by 4X. Magnification power (Mag) of a two lens setup can be calculated by dividing the focal length of the second lens (f2) by the focal length of the first (f1).
(4) One way to achieve the required magnification is to use a 25mm diameter x -25mm EFL PCV Cylinder Lens with a 25mm diameter x 100mm EFL PCX Cylinder Lens. Two PCX cylinder lenses can also be used, but add additional length to the system. The use of cylinder lenses also decreases beam divergence, increasing the beam’s collimation, which is ideal for long distance projection applications. To help in selecting the right cylinder lens for any application, refer to Table 1.
Cylinder Lens Selection Guide Table 1: Cylinder Lens Selection GuideTypeWavelengthIdeal Application Fast Axis Collimators 0.8 – 1.0μm Collimating high power laser diode bars Illunimation PCX Cylinder Lenses 0.4 - 1.6μm Focusing a laser to a line or circularizing a laser beam UV Fused Silica PCX Cylinder Lenses 0.2 - 2.2μm Operating in harsh or rugged environments Achromatic Cylinder Lenses 0.4 - 1.0μm Creating line profiles of broadband light sources Plastic Hybrid Acylinder Lenses 0.4 - 1.6μm Creating line profiles of broadband light sources Illumination PCV Cylinder Lenses 0.4 - 1.6μm Beam expansion Cylindrical Microlens Arrays 0.2 - 2.2μm Beam homogenization
Cylinder lenses are a type of lens that have differing radii in the X and Y axes, causing the lens to have a cylindrical or semi-cylindrical shape, and image magnification in only a single axis.Cylinder lensesare commonly used as laser line generators, or to adjust image height size or correct for astigmatism in imaging systems.
Figure 1:Plano-Convex Circular Cylinder Lens Figure 2:Plano-Convex Rectangular Cylinder Lens Figure 3:Plano-Convex Oblong Cylinder Lens Creating a Laser Line Generator When using a cylinder lens as a laser line generator, it is important to calculate the required Effective Focal Length (EFL) for the application. To do so, first calculate the fan angle (θ) using the needed line length (x) at the given working distance (L) in centimeters:
(1) The fan angle can also be used to determine the line length at a given working distance:
(2) Figure 4:Visual Illustration of Equations 1 – 2 for Creating a Laser Line Generator The EFL can then be calculated using the input beam radius (d/2) and the following equation:
(3) Figure 5:Visual Illustration of Equation 3 for Calculating Effective Focal Length Creating Circular Beams Typically,laser diodesemit elliptical shaped beams that may be unsuitable for applications that require a collimated, circular laser source. Using twocylinder lensesis a common method to circularize an elliptical beam - the first lens magnifies the minor axis of the laser diode, and the second lens collimates the beam. The curved side of the lenses and the minor axis of the laser diode should be oriented so that the minor axis is being magnified.
For example, to modify an elliptical beam with a 4.0mm major axis and a 1.0mm minor axis to a circular beam with a 4.0mm diameter, the minor axis needs to be magnified by 4X. Magnification power (Mag) of a two lens setup can be calculated by dividing the focal length of the second lens (f2) by the focal length of the first (f1).
(4) One way to achieve the required magnification is to use a 25mm diameter x -25mm EFL PCV Cylinder Lens with a 25mm diameter x 100mm EFL PCX Cylinder Lens. Two PCX cylinder lenses can also be used, but add additional length to the system. The use of cylinder lenses also decreases beam divergence, increasing the beam’s collimation, which is ideal for long distance projection applications. To help in selecting the right cylinder lens for any application, refer to Table 1.
Cylinder Lens Selection Guide Table 1: Cylinder Lens Selection GuideTypeWavelengthIdeal Application| Fast Axis Collimators | 0.8 – 1.0μm | Collimating high power laser diode bars |
| Illunimation PCX Cylinder Lenses | 0.4 - 1.6μm | Focusing a laser to a line or circularizing a laser beam |
| UV Fused Silica PCX Cylinder Lenses | 0.2 - 2.2μm | Operating in harsh or rugged environments |
| Achromatic Cylinder Lenses | 0.4 - 1.0μm | Creating line profiles of broadband light sources |
| Plastic Hybrid Acylinder Lenses | 0.4 - 1.6μm | Creating line profiles of broadband light sources |
| Illumination PCV Cylinder Lenses | 0.4 - 1.6μm | Beam expansion |
| Cylindrical Microlens Arrays | 0.2 - 2.2μm | Beam homogenization |
