Image forming optical system
US7944627B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 31, 2009 |
| Grant date | May 17, 2011 |
| Priority date | — |
| Expiry date | Dec 31, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B13/004
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
To provide a compact image forming optical system in which an incident angle to an imaging plane of a solid-state imaging device is small and whose chromatic aberration, astigmatism, field curvature, and distortion are reduced. An image forming optical system of a first embodiment of the present invention comprises four lenses arranged from the object side to the imaging plane side in order, that are a first lens that is a double-convex lens, a second lens that is a double-concave lens, a third lens that is a positive meniscus lens that is convex toward an image side, and a fourth lens that is a negative meniscus lens that is convex toward an object side. An aperture is placed closer to the object than the image side surface of the first lens. The image forming optical system of the first embodiment of the present invention satisfies the following equations, where fi is an absolute value of a focal length of i-th lens, f is an absolute value of a focal length of a whole optical system, vdi is Abbe's number of i-th lens, and TTL is a distance from the object side surface of the first lens, in the object side surface and an aperture side surface, to the imaging plane.0.425<f1/f4<0.7 …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.