Imaging of the actual optical system is incomplete. When light passes through every surface of an optical system, various aberrations are induced, resulting in blurred images, distortions, and other defects. Aberration is a description of the degree of imperfection in the imaging of an optical system. It is especially important to correct the aberrations and imaging effects of the individual optical elements in the optical system.

Optical lenses focus or diverge light to form an image of an object at the desired location. It is an integral part of optical imaging and illumination systems. When light is transmitted, it is affected by the refraction, reflection, diffraction, defects and other factors of optical components, resulting in spherical aberration, coma, astigmatism, field curvature, distortion, and chromatic aberration, which will produce the final imaging effect of the entire optical system. influences. In addition to perfect and rational optical system design, achromatic lenses and high-quality optical components are often used to correct aberrations.

Spherical aberration, coma and astigmatism can be eliminated at certain special points of the lens. Such lenses not only meet the large aperture requirements of the entire objective system, but are also commonly used in the design of large aperture microscope objectives. Not only that, but aberrations are also beneficial. stable. However, in other cases where lenses are used, the distance between the lens and the object is often not fixed. Therefore, a single lens cannot fully meet the requirements of correcting aberrations, and lens combinations and achromatic lenses are often used in optical systems to correct aberrations.

Achromatic lenses are designed for broadband applications such as astronomy, color photomicrography, plasma spectroscopy, and biomedical devices.

They consist of two or more lens elements, where the lens elements are made of different glass materials, usually correct for chromatic aberration at blue and red wavelengths, and mutually correct for the chromatic aberration of two single lenses. Apochromatic lenses compensate for the third wavelength to minimize spherical and chromatic aberration at the three wavelengths and are often used for precision microprocessing and imaging. UV achromats are ideal for broadband UV spectral applications such as optical instrumentation and fluorescence analysis. In some cases, it can also be used as a focusing lens instead of a condenser lens.