Observation optical system, viewfinder equipped with observation optical system and method for manufacturing observation optical system
US-9454062-B2 · Sep 27, 2016 · US
Eyepiece lens and imaging apparatus
US9678328B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9678328-B2 |
| Application number | US-201514726615-A |
| Country | US |
| Kind code | B2 |
| Filing date | Jun 1, 2015 |
| Priority date | Jun 11, 2014 |
| Publication date | Jun 13, 2017 |
| Grant date | Jun 13, 2017 |
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Abstract
Official abstract text for this publication.
An eyepiece lens consists essentially of a first lens having positive refractive power, a second lens having negative refractive power, a third lens having positive refractive power, and a fourth lens having positive refractive power in this order from an observation object side. Conditional expression (1): −3.5<f/fA<0.0 is satisfied, where f: a focal length of an entire system, and fA: a combined focal length of the first lens and the second lens.
First claim
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What is claimed is: 1. An eyepiece lens consisting of: a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; and a fourth lens having positive refractive power in this order from an observation object side, and the fourth lens is a meniscus lens with a convex surface facing an eye point side, wherein the following conditional expression (1) is satisfied: −3.5< f/fA< 0.0 (1), where f: a focal length of an entire system, and fA: a combined focal length of the first lens and the second lens, wherein the following conditional expression (4) is satisfied: −4.0< f/R 2 f<− 2.0 (4), where R2f: a paraxial curvature radius of an object-side surface of the second lens. 2. The eyepiece lens, as defined in claim 1 , wherein the following conditional expression (2) is satisfied: 1.0< f/fB< 2.1 (2), where fB: a combined focal length of the third lens and the fourth lens. 3. The eyepiece lens, as defined in claim 1 , wherein the following conditional expression (3) is satisfied: −5.0< f/f 2<−1.2 (3), where f2: a focal length of the second lens. 4. The eyepiece lens, as defined in claim 1 , wherein the following conditional expression (1-2) is satisfied: −2.0< f/fA< 0.0 (1-2). 5. The eyepiece lens, as defined in claim 1 , wherein the following conditional expression (1-3) is satisfied: −1.5< f/fA<− 0.5 (1-3). 6. The eyepiece lens, as defined in claim 2 , wherein the following conditional expression (2-2) is satisfied: 1.5< f/fB< 2.0 (2-2). 7. The eyepiece lens, as defined in claim 3 , wherein the following conditional expression (3-2) is satisfied: −2.5< f/f 2<−1.5 (3-2). 8. The eyepiece lens, as defined in claim 1 , wherein the following conditional expression (4-2) is satisfied: −3.5< f/R 2 f<− 2.5 (4-2). 9. An imaging apparatus comprising: the eyepiece lens, as defined in claim 1 .
Assignees
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Classifications
- G02B25/001Primary
Eyepieces · CPC title
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- What does patent US9678328B2 cover?
- An eyepiece lens consists essentially of a first lens having positive refractive power, a second lens having negative refractive power, a third lens having positive refractive power, and a fourth lens having positive refractive power in this order from an observation object side. Conditional expression (1): −3.5<f/fA<0.0 is satisfied, where f: a focal length of an entire system, and …
- Who is the assignee on this patent?
- Fujifilm Corp
- What technology area does this patent fall under?
- Primary CPC classification G02B25/001. Mapped technology areas include Physics.
- When was this patent published?
- Publication date Tue Jun 13 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 3 related publications on this page (citations in our corpus or others sharing the same primary CPC).