The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 28, 1999
Filed:
Jun. 03, 1998
Yuka Adachi, Aichi-ken, JP;
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An achromatic lens system comprising a front lens group, a diffraction lens and a rear lens group, in this order from the object side, wherein; the front lens group is provided with a frontmost convex surface on the object side and a rearmost concave surface on the image side; the rear lens group is provided with a rearmost convex surface on the image side; the front and rear lens groups are arranged to generate under-axial chromatic aberration for blue light and generate over-axial chromatic aberration for red light, with respect to green light that is considered the reference light; and, achromatic correction of light in the visible region is conducted by correcting the axial chromatic aberrations with a diffracting function of the diffraction lens.