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1、Using Cyli nder Len sesCyli nder len ses are a type of lens that have differi ng radii in the X and Y axes, caus ing the lens to have cylindrical or semi-cylindrical shape, and image magnification in only a single axis.Cylinder lenses are commonly used as laser line generators, or to adjust image he

2、ight size or correct for astigmatism in imagi ng systems.Figure 1a: Plano-Con vex Circular Cyli nder LensFigure 1c: Plano-Convex Oblong Cylinder LensCreating a Laser Line Generator)usingWhen using a cylinder lens as a laser line generator, it is important to calculate the required Effective Focal Le

3、ngth (EFL) for the application. To do so, first calculate the fan angle ( len gth (x) at the give n work ing dista nee (L) in cen timeters:The fan angle can also be used to determine the line length at a given working distanee:The EFL can the n be calculated using the in put beam radius (d/2) and th

4、e follow ing equati on:Figure 2: Visual Illustration of Equations 1-2 for Creating a Laser Line GeneratorEFLFigure 3: Visual Illustration of Equation 3 for Calculating Effective Focal LengthCreating Circular BeamsTypically, laser diodes emit elliptical shaped beams that may be un suitable for applic

5、ations that require a collimated, circular laser source. Using two cylinder lenses is a commormethod 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 len ses and the minor axis of the laser

6、diode should be orie nted so that the minor axis is being magn ified.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.Magnificationpower (Mag) of a two lens setup can be calcu

7、lated by dividing the focal lengthof the sec ond lens (f2) by the focal le ngth of the first (f1).咖=KOne way to achieve the required magnification is to use a 25mm diameter x -25mm EFL PCVCylinder Lens (#46-196) with a 25mmdiameter x 100mmEFL PCXCylinder Lens (#46-018). Two PCX cyli nder len ses can

8、 also be used, but add additi on al le ngth to the system. The use of cyli nder len sesalso decreases beam diverge nee, in creas ing the beam s collimati on,which is ideal for long dista nee project ion applicati ons. To help in select ing therightcylinder lens for any application, refer to Table 1.

9、Table 1: Cylinder Lens Selection GuideTypeWavele ngthIdeal Applicati onFast Axis Collimators0.8 -1.0 (imCollimat ing high power laser diode barsPCX Cyli nder Len ses0.4 - 1.6 (imFocus ing a laser to a line or circulariz ing a laser beamUV Fused Silica PCX Cylinder Lenses0.2 - 2.2 (imOperat ing in harsh or rugged environmentsAchromatic Cyli nder Len ses0.4 - 1.0 (imCreating line profiles of broadband light sourcesPlastic Hybrid Acylinder Lenses0.4 - 1.6 (imCreating l