Cylindrical lenses are aspherical lenses, which can effectively reduce spherical aberration and chromatic aberration. Cylindrical lenses are divided into plano-convex cylindrical lenses, plano-concave cylindrical lenses and cylindrical lenses.
The cylindrical lens has a one-dimensional magnification function and is mainly used in the design requirements of changing the imaging size, such as converting a spot light spot into a line spot, or changing the height of the image without changing the width of the image.
Cylindrical lens uses are in linear detector lighting, barcode scanning, holographic lighting, optical information processing, computers, laser emission, etc. Cylindrical optical lenses are also widely used in strong laser systems and synchrotron radiation beams.
With more and more applications, the requirements for cylindrical lenses are also getting higher and higher, especially in high-precision testing instruments and devices such as high-power laser resonator chips and long-distance line interferometers.
The production process of cylindrical mirror mainly includes rough grinding, fine grinding, polishing, centering and edging.
1. Rough grinding cylindrical lens
Usually, the rough grinding of the small radius cylindrical mirror is to glue the square blank to the mold, form a cylinder and then process the outer circle to obtain a cylindrical surface. Parts whose thickness is equal to or greater than the radius of curvature R of the cylindrical surface are generally rough ground into a whole cylinder first, and then finish grinding and polishing, and then grind off the excess part.
The rough grinding of the cylindrical lens can use a conventional cylindrical grinder, but if the diameter of the cylindrical lens is small, a centerless grinder should be used.
Generally, when the number of cylindrical mirrors is not large, the four corners of the square blank can also be ground by hand on a rough grinder, and then the cylinder can be installed on the main shaft of the instrument lathe.
Then install a flat iron plate inclined at a certain angle to the horizontal plane on the lathe tool holder to process the outer circle. Rough grinding of cylindrical mirrors with a medium or higher radius of curvature can be formed by milling.
2. Fine grinding cylindrical mirror
For the fine grinding of the small radius cylindrical optical lens, when the number of products is small, the method of adding the instrument lathe manually can still be used, and the detail is to replace the fine grinding abrasive.
In mass production, the upper and lower flat grinding is generally used, and the separator is clamped in the middle. During the fine grinding process, the cylinder should be turned around regularly to avoid grinding into a cone. Another way to fix the separator is to shift the intermediate mandrel by the outer retaining ring.
For cylindrical mirrors with a medium radius, after milling and forming, they are often glued to the mold to form an ir dichroic mirror column for fine grinding, and then install the mirror column on the main shaft of the lathe, and then install the mold on the lathe tool holder and add loose abrasives for fine grinding.
For concave cylindrical mirrors and large-radius cylindrical lenses that are not suitable for glueing into cylinders, they are often glued into mirror discs first, and then finely ground with corresponding cylindrical molds on a special cylindrical machine tool.
3. Cylindrical mirror polishing
The processing method of polishing is similar to fine grinding. Generally, there is a layer of felt with a thickness of 3~5mm on the polishing mold, and the length of the polishing mold is about 1/3 of the length of the cylinder.