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- An aspheric lens corrects spherical aberration by continuously varying its radius of curvature, an essential technology for larger apertures and wider angles in photographic lenses<\/li>\n\n\n\n
- Manufacturing methods fall into three broad categories \u2014 grinding and polishing, glass molding, and resin injection molding \u2014 each with a different balance of precision, mass-producibility, and cost<\/li>\n\n\n\n
- Resin injection molding excels at freeform surfaces and mass-producibility, but heat resistance, the temperature dependence of refractive index, and birefringence control remain design challenges, so the property design of the optical resin itself determines performance<\/li>\n\n<\/ul>\n\n\n\n
\n\n\n\nWhat is an aspheric lens?\n\u2014 a lens shape that corrects spherical aberration<\/h2>\n\n\n\n
A spherical lens has the shape of a section cut from a sphere. It is easy to process and keeps costs down, but it inherently produces spherical aberration, in which the focal position for paraxial rays passing through the lens center does not coincide with that for rays passing through the periphery (Optical and Electronic Equipment Development & Production Partner.com, types of optical lenses<\/a>). An aspheric lens adopts a curved surface that a sphere cannot express, reducing spherical aberration by varying the curvature from place to place (Katsura Opto-System, what is an aspheric lens<\/a>).<\/p>\n\n\n\n
In photographic lenses, aspheric shapes are particularly effective for correcting spherical aberration in large-aperture lenses and distortion in ultra-wide-angle and zoom lenses (Panasonic, digital camera course, spherical lenses and aspheric lenses<\/a>). In optical systems that demand both compact, thin form factors and high imaging performance at once \u2014 such as smartphone cameras, automotive cameras, and XR devices \u2014 using an aspheric shape is now almost a given.<\/p>\n\n\n\n
\n\n\n\nWhat is aberration?\n\u2014 classifying imaging errors, with spherical aberration at the center<\/h2>\n\n\n\n
Aberration is a measure of deviation from ideal image formation, and it is classified into two categories: monochromatic aberration and chromatic aberration. Monochromatic aberration is further divided into five types, known as the Seidel aberrations: spherical aberration, coma, astigmatism, field curvature, and distortion (Opticallensdesign.com, fundamentals of optical design: types of aberration<\/a>).<\/p>\n\n\n\n
Spherical aberration arises when rays from an on-axis object point enter a lens: rays with a larger numerical aperture are refracted more strongly and cross the optical axis at a point offset from the ideal image position. Coma is the phenomenon in which light from an off-axis object point fails to converge to a single point on the image plane and instead trails off in a comet-like shape; astigmatism, in which the focal position differs between two mutually perpendicular directions, is the optical equivalent of astigmatism in the human eye. Field curvature is the phenomenon in which the image of a flat subject forms on a curved surface, and distortion is a warping of the image shape itself. Chromatic aberration arises because a medium’s refractive index depends on wavelength, and it splits into axial and lateral chromatic aberration.<\/p>\n\n\n\n
![\"\"](\"https:\/\/iupizeta.mgc.co.jp\/cms\/wp-content\/uploads\/2026\/08\/spherical_aberration.png\")
<\/figure>\n\n\n\nAn aspheric lens primarily targets spherical aberration for correction, but suppressing chromatic aberration separately requires Abbe number design on the material side, and the two are treated as independent design parameters.<\/p>\n\n\n\n
\n\n\n\nHow aspheric lenses are manufactured\n\u2014 grinding and polishing, glass molding, and resin injection molding<\/h2>\n\n\n\n
Manufacturing methods for aspheric shapes fall broadly into three categories.<\/p>\n\n\n\n