Objective optical system
AssigneeOlympus Medical Systems Corp.
InventorHideyasu Takato
Life of this patent
Estimating the term…
Abstract
Provided is a high-performance objective optical system which is compatible with a high-pixel-count image acquisition device, in which focusing can be achieved according to a change in object point distance and which has sufficient depth of field at the individual object point distances. Provided is an objective optical system (1) including, in order from an object side, a first group (G1), a second group (G2), and a third group (G3), in which the first group (G1) includes, in order from the object side, a plano-concave lens (L1) and a meniscus lens (L2) whose convex surface is towards an image side and in which the second group (G2) includes a positive meniscus lens whose convex surface is towards the object side and moves in the direction of an optical axis to perform focusing.
Claims5
An objective optical system comprising, in order from an object side, a first group, a second group, and a third group, wherein
- the first group includes, in order from the object side, a plano-concave lens and a meniscus lens whose convex surface is towards an image side;
- and
- the second group includes a positive meniscus lens whose convex surface is towards the object side and moves in a direction of an optical axis to perform focusing.
An objective optical system comprising, in order from an object side, a plano-concave lens, a meniscus lens whose convex surface is towards an image side, a positive meniscus lens whose convex surface is towards the object side, an aperture stop, a first positive lens having convex surfaces at both sides, and a joined lens composed of a second positive lens and a negative lens, and satisfying the following Conditional Expression (3):
- 0.08<d/f<0.32 (3)
- where
- d:
- the air gap between the meniscus lens and the first positive lens.
Dependencies are inferred from the claim text.