Image reading lens, image optical system and image reader
US7483221B2 · kind B2 · utility
5Cited by
4References
21Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 19, 2007 |
| Grant date | Jan 27, 2009 |
| Priority date | — |
| Expiry date | Aug 7, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B15/10
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An image reading lens is provided and includes: first, second and third lens groups arranged on the object side with respect to the aperture stop; and fourth, fifth and sixth lens groups arranged on the image side. At least all positive lenses, in each lens group, satisfy conditional expression (1) below. At least two positive lenses of the first to third lens groups and at least two positive lens of the fourth to sixth lens groups satisfy the conditional expression (2) below. In the conditional expressions, νd represents Abbe number at the d-line, and Δθg,d represents abnormal dispersion.νd>60.0 (1)Δθg,d>0.015 (2)
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.