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US 5,636,065 AGranted
Triplet lens system
AssigneeOlympus Optical Co., Ltd.
InventorHideyasu Takato
Life of this patent
Estimating the term…
Abstract
A triplet lens system comprising, in order from the object side, a first positive meniscus lens component having a convex surface on the object side, a second biconcave lens component, a third biconvex lens component and a stop; and configured so as to correct aspherical aberration and coma at the same time by using at least one aspherical surface on the second and the third lens components.
Claims4
A triplet lens system comprising in order from the object side:
- a first positive meniscus lens component having a convex surface on the object side;
- a second biconcave lens component;
- a third biconvex lens component;
- and
- a stop,
- wherein at least one of said second lens component and said third lens component has an aspherical surface, wherein said triplet lens system satisfies the following conditions (1) and (2);
- 1.times.10.sup.-5 <.vertline.x.sub.1 /f .vertline.<1.times.10.sup.-2( 1)
- 0.5<r.sub.5 /f<1.1 (2)
- wherein the reference symbol x.sub.1 represents a departure from a reference sphere of at least one of said aspherical surface as measured at a maximum effective diameter thereof, the reference symbol r.sub.5 designates a radius of curvature on an object side surface of said third lens component and the reference symbol f denotes a focal length of said triplet lens system as a whole;
- and
- said lens system has an F-number significantly less than 3.5.
8 more elements
Dependencies are inferred from the claim text.