Plano convex lenses can be used for focusing, collecting, and collimating light rays. In the case where the distance between the object image and the lens is not equal, the asymmetry of the lens shape will minimize the spherical aberration. The best scenario is to place the object at infinity, with light rays entering the lens in parallel and ultimately forming an image at the focal point. Commonly used flat convex lens H-K9L or ultraviolet fused quartz (JGS1) glass. H-K9L glass is the most common optical glass that provides excellent optical performance and is reasonably priced. The characteristics of H-K9L, such as low bubbles, low impurities, and easy manufacturing, make it an excellent lens material for visible and near-infrared applications. Ultraviolet fused silica is in the wavelength range of 185 to 2100 nm. It has excellent transmissivity in the ultraviolet region, does not emit fluorescence under ultraviolet light, and is radiation resistant. Compared with other optical glasses (such as K9), UV fused silica has lower refractive index, lower thermal expansion coefficient and better uniformity at a certain wavelength.