The plane convex cylindrical lens forms a linear image, which is used to control the size of only one direction of the beam. The material of this lens is BK7, so it is not suitable for ultraviolet wavelength. Compared with spherical lens, cylindrical lens is more difficult to manufacture. Materials (texture, bubbles, impurities, uniformity) should be selected reasonably, and factors affecting scattered (scratches, dents, gloss) should be paid attention to, with high-quality grinding. It can be divided into uncoated and visible band coated antireflection multilayer lens. The design wavelength of the lens is 546.1 nm (E-line of green mercury line). Since the focal length changes with the wavelength, when it is used for other wavelengths, the focal length also changes.