ALEXANDRIA, Va., July 3 -- United States Patent no. 12,345,857, issued on July 1, was assigned to CANON K.K. (Tokyo).
"Optical system and image pickup apparatus" was invented by Hiroki Ebe (Tochigi, Japan) and Shinichiro Saito (Tochigi, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "An optical system consists of a front unit and a rear unit. The front unit consists of a first lens having a positive refractive power, a second lens disposed on an image side of the first lens and having a positive refractive power, and a third lens. Each of the first lens and the second lens has a refractive index of 1.7 or higher for d-line. The rear unit consists of two or more and four or fewer lenses and includes a fo...