Objective Lens and Observation Apparatus Having the Same
US-2015268460-A1 · Sep 24, 2015 · US
Endoscope objective optical system
US9817226B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9817226-B2 |
| Application number | US-201615358768-A |
| Country | US |
| Kind code | B2 |
| Filing date | Nov 22, 2016 |
| Priority date | Sep 22, 2014 |
| Publication date | Nov 14, 2017 |
| Grant date | Nov 14, 2017 |
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Abstract
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Provided is an endoscope objective optical system including, in order from an object side, a first group having negative refractive power, a second group having positive refractive power, and a third group having positive refractive power. The second group is provided so as to be movable in an optical-axis direction. The following conditional expression is satisfied, 9< f 2/ fa <16 (1) where f2 is a focal length of the second group, and fa is a focal length of the entire system in the normal observation state.
First claim
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The invention claimed is: 1. An endoscope objective optical system consisting of, in order from an object side, a first group having negative refractive power, a second group having positive refractive power, and a third group having positive refractive power, wherein the second group comprises a single plano-convex lens and moves in an optical-axis direction to perform focusing from a normal observation state to a close observation state, wherein all other lens elements within the objective optical system are stationary during focusing; and wherein the following conditional expression is satisfied, 9< f 2/ fa< 16 (1) where f2 is a focal length of the second group, and fa is a focal length of the entire system in the normal observation state. 2. An endoscope objective optical system according to claim 1 , wherein the following conditional expression is satisfied, 0.2< l/fa< 0.3 (2) where l is a movement distance of the second group associated with focusing, and fa is a focal length of the entire system in the normal observation state. 3. An endoscope objective optical system according to claim 2 , wherein the following conditional expression is satisfied, 1.3< d 0 a/d 0 b< 3.5 (3) where d0a is an object distance in the normal observation state, and d0b is an object distance in the close observation state.
Assignees
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Classifications
Optical elements · CPC title
characterised by multiple eyepieces · CPC title
- G02B23/243Primary
Objectives for endoscopes · CPC title
characterised by variable lenses · CPC title
with mechanism for focusing or varying magnification · CPC title
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- What does patent US9817226B2 cover?
- Provided is an endoscope objective optical system including, in order from an object side, a first group having negative refractive power, a second group having positive refractive power, and a third group having positive refractive power. The second group is provided so as to be movable in an optical-axis direction. The following conditional expression is satisfied, 9< f 2/ fa <16 (1) whe…
- Who is the assignee on this patent?
- Olympus Corp
- What technology area does this patent fall under?
- Primary CPC classification G02B23/243. Mapped technology areas include Physics.
- When was this patent published?
- Publication date Tue Nov 14 2017 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 2 related publications on this page (citations in our corpus or others sharing the same primary CPC).